In verse 10, St. John showed that the Incarnation was necessary for us, because “the world knew him not.” In verse 12, he shows how we benefited by the Incarnation, in that we received the power to become adopted sons and daughters of God.

“He came to his own home” (Jn 1:11a) that we might know Him there. The world is His home because He created it: “The earth is the Lord’s and the fulness thereof, the world and those who dwell therein” (Ps 24:1). Because He continually conserves every creature in being, He must have been in the world from the moment of creation. Since God is present everywhere, as we said above (Lect. 5), when He became incarnate in the womb of the Virgin Mary, He did not cease being where He had been before. He came to Judea, and not to some other land, because it was written, “In Judah God is known” (Ps 76:1).

One can come to a place in two ways. First, absolutely, as when one comes to a place where one has never been before. Second, one can come to a place where one has been before, but now begins to be there in a new way, as a king who was previously “in” a certain city, insofar as he exercised power over the city, now visits that city in person. It is in this second way that the Word came to us in the flesh. When God became man, He came to a place where He was already present, conserving His creatures in being. But now He made Himself present in a new way, so that henceforth, we knew the Word of God as the Son of God, a divine person with two complete natures, divine and human. He takes His divine nature from the Father and is eternally begotten of the Father. He takes his human nature from the Virgin Mary and was born to her in the fullness of time, at the precise moment in history when it was most fitting that the Savior of mankind should come. Before the Incarnation, the Word was in the world invisibly. He came in the flesh in order to reveal Himself visibly to us.

“And his own people received him not” (Jn 1:11b). God chose the Jews and set them apart to be His own special people, as we read in the Book of the Law: “The Lord has declared this day concerning you that you are a people for his own possession” (Dt 26:18). The Word of God spoke to their patriarchs and gave Moses the law. It was, therefore, to be expected, that when He came as man in the person of Christ, He would first of all come to the Jews. St. Paul explained: “Christ became a servant to the circumcised to show God’s truthfulness, in order to confirm the promises given to the patriarchs” (Rom 15:8). Though Christ came to His own people, they, by and large, rejected Him. Subsequently, the apostles had greater success spreading the gospel among the Gentiles.

The Evangelist tells us three things about the fruit of His coming to us as man: he indicates to whom the fruit is given, he speaks of the grandeur of the fruit, and he shows the way in which the fruit is given.

1. To whom is given the fruit of His coming. “But to all who received him, who believed in his name” (Jn 1:12a) indicates that God’s grace extends to anyone who accepts it, whether he be Jew or Gentile. St. Paul noted, “By one Spirit we were all baptized into one body–Jews or Greeks, slaves or free” (1 Cor 12:13). This is because “There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus” (Gal 3:28). From this it follows, according to the Apostle, that “If you are Christ’s, then you are Abraham’s offspring, heirs according to the promise” (Gal 3:29).

We can understand the relation of the phrases, “received him” and “believed in his name,” in two different ways. First, we can take the second statement to be an explanation of the first. In this sense, to receive Christ is to believe in Him, for it is through our faith that Christ dwells in our hearts. In this way, St. Paul prayed (Eph 3:17) that Christ might dwell in the hearts of the Ephesians. Second, we can take the second statement to be a qualification of the first. Origen noted that many “receive” Christ by declaring themselves to be Christians, but soon fall away from the true faith. These heretics did not really “believe in His name” in the first place, for they denied some aspect of the hypostatic union, making Him less than fully divine or less than fully human. They denigrated the holy name of Jesus Christ. St. John cautioned his neophytes: “Every spirit which does not confess Jesus is not of God. This is the spirit of antichrist.” (1 Jn 4:3). Those who possess the “power to become children of God” are those who not only declare themselves to be Christians, but who respect the name of Christ is such a way as not to diminish His divinity or humanity. Their faith is formed by charity, for they do good works, cooperating with grace. When Christ died on the cross, He merited for us the grace of salvation. When a justified man performs good works while in the state of grace, he merits eternal life, thereby completing the salvific work of Christ. By contrast, those who have an unformed faith do not follow the teaching and example of Christ; they are without charity, like trees that bear no fruit.

2. The grandeur of the fruit. “He gave power to become children of God” (Jn 1:12b). This fruit is great because it raises us to the status of adopted sons and daughters of God. St. Paul taught the Galatians: “When the time had fully come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons” (Gal 4:4-5). It was fitting that the human creature, who bears a certain spiritual likeness to God, should be reshaped by the Son of God into an even greater spiritual likeness. We become children of God according to a threefold likeness. First, we attain a likeness of God by the infusion of grace. One who is sanctified by grace becomes a son of God, and at that moment, he receives the gift of the Holy Spirit and becomes an heir to the kingdom of heaven. St. Paul explained: “Because you are sons, God has sent the Spirit of his Son into our hearts, crying, ‘Abba! Father!’ So through God you are no longer a slave but a son, and if a son then an heir.” (Gal 4:6-7) Slaves cannot inherit their master’s wealth, but sons are free to do so. The privileged status we lost on account of our self-imposed slavery to sin was regained for us by Christ. On account of Him, and through His grace, we now have the freedom, as adopted sons and daughters of God, to receive the blessings God wishes to bestow upon each of us who believes in Him and follows His Son. Such an extraordinary moral emancipation means that we have been given a second chance to experience eternal life. “The wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord” (Rom 6:23). Realizing the enormity of this gift, St. Paul cautioned the Romans: “You did not receive the spirit of slavery to fall back into fear, but you have received the spirit of sonship” (Rom 8:15). Second, we attain a likeness of God by the perfection of our actions. A son of God is one who acts with justice and mercy, for a son is like his father, and God the Father is just and merciful. Christ counseled us to temper justice with mercy: “Love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven” (Mt 5:44-45). He noted (Mt 5:46-47) that there is no reward in loving those who love us. Instead, the perfection of virtue consists in loving those who hate us. Christ urges us to “be perfect, as [our] heavenly Father is perfect” (Mt 5:48), for we attain a likeness of God by the perfection of our actions. Third, we attain a likeness of God by the attainment of glory, and this likeness will be manifested both in our souls and in our glorified bodies in the life to come. Concerning the glory of the soul, we see how St. John looked forward to the day when Christ will return in glory, and on that day the light of His glory will shine upon the souls of the faithful: “Beloved, we are God’s children now; it does not yet appear what we shall be, but we know that when he appears we shall be like him, for we shall see him as he is” (1 Jn 3:2). Concerning the glory of the body, St. Paul said, “Our commonwealth is in heaven, and from it we await a Savior, the Lord Jesus Christ, who will change our lowly body to be like his glorious body” (Phil 3:20-21).

How does the infusion of grace give us “power to become children of God”? If this power is a power of nature, a power that is natural for man to possess, then this statement would seem to be false, for the infusion of grace is beyond our natural ability, and infused grace is above human nature. On the other hand, if the power to become a child of God is the power of grace, then this power is really not a power to become, but a power to be, for grace raises us to the status of adopted children of God. To solve this difficulty, we must realize that although God offers us grace, we must accept it in order for it to be efficacious for us. When we do accept sufficient grace, it becomes for us efficacious grace. Grace is freely given and must be freely accepted. God alone has the power to freely give sanctifying grace to whomever He chooses in whatever measure He chooses, and the recipient alone has the power to freely accept it or to reject it. Thus, the “power to become children of God” is the power of men to accept grace when it is offered.

Man’s possession of a rational intellect and an intellectual appetite (a will) is not all he needs to gain him eternal life. His will must be moved to accept supernatural grace. God gives us the power to accept grace by preparing us to receive it. This preparatory grace is called movent grace or prevenient grace. It is an actual grace that moves the will to be open to receive sanctifying grace (habitual grace). It is God calling us, beckoning us to accept the grace of salvation, as St. Paul said, “those whom he called he also justified” (Rom 8:30). Prevenient grace enables a man enveloped in the darkness of sin and ignorance to respond to God’s call, to have the courage to raise his head enough to see the light of Christ and to accept His grace. Man experiences this calling within his soul, which is the part of him that is most like his Creator.

The power of grace also enables us to live virtuously in accord with human nature and to shun vice, thereby allowing us to remain children of God. St. John wrote, “Any one born of God does not sin, but He who was born of God keeps him, and the evil one does not touch him” (1 Jn 5:18). Grace preserves us from sin, but we must continually accept His grace in order to remain sinless.

Therefore, we attain a likeness to God in three ways: by the infusion of grace, by the perfection of our actions, and ultimately by the attainment of glory in body and soul. To become a child of God by the infusion of grace requires three actions: first God prepares an individual to accept sanctifying grace, then He moves his will, and finally He preserves him in grace.

3. The way in which the fruit is given. The Evangelist added the line, “who were born, not of blood nor of the will of the flesh nor of the will of man, but of God” (Jn 1:13), to dismiss any suggestion that the power to become a child of God is something passed from father to son by material generation, that is, through a willful conjugal act. One does not become a child of God simply because he is born to Christian parents. Sexual intercourse gives rise to the conception of a body, but God creates each soul immediately and joins it to that body. One becomes a child of God, not carnally, but spiritually. Hence, a person born spiritually is said to be reborn. The first birth is physical, the second, spiritual. Since a child of God is born of God, Who is pure spirit, the rebirth of a child of God is a spiritual birth. Thus, Jesus said to Nicodemus, “That which is born of the flesh is flesh, and that which is born of the Spirit is spirit” (Jn 3:6).

There is a difference between Christ’s sonship and the sonship of the adopted children of God. It concerns the manner in which a term has its origin from its principle. A term proceeds from a principle either by internal procession, as in the case of God the Son proceeding eternally from God the Father, or by external procession, as in the case of creation.

There are three Latin prepositions used to denote the origin of a thing: a, ex, and de. Since the same English word, “from,” has been used to denote all three, it is useful to distinguish these three prepositions from each other. First, the preposition “a” signifies motion, the agent of which is the efficient cause. Second, the preposition “ex” signifies origin, in the sense that one thing (a term) comes from another (a principle), such that the term has its origin in its principle. The term comes out of the principle in some way, or exists in a certain way on account of its principle. This implies that the principle is both the efficient cause and the material cause of the term; but it does not imply that the term and the principle are necessarily of the same nature. Third, the preposition “de” signifies an efficient cause and a material cause, and even a consubstantial cause, as a blacksmith forges a knife blade de ferro (from iron) in such a way that the iron and the blade are of the same substance, or as a father generates a son de seipso (from himself) in such a way that father and son are of the same nature.

Concerning the relationship between an offspring and his natural parent, we observe that an offspring of a living thing necessarily has the same nature as its parent, for the offspring has its origin in its parent by generation. Thus each of us takes our human nature from our parents, as Jesus took His human nature from the Virgin Mary, when He was conceived by the power of the Holy Spirit.

Concerning the relationship between men and God, all sons of God are said to be a Deo (from God) in some sense. Christ is a Deo in the sense that He is de Deo, that is, from the Father by an act of generation. Because a natural offspring of a living thing has the same nature as its parent, the Son is consubstantial with the Father. But as for the rest of us, we are a Deo, inasmuch as God is our Creator and the Author of life, but we are not de Deo, for we do not proceed from God by generation, but by creation.

When the Evangelist speaks of the Son of God (Filius de Deo), he uses the preposition de, which implies that the Father and the Son are of the same nature. But in verse 13, we read that a child of God is ex Deo, which does not imply that the adopted child and his heavenly Father are of the same nature, for a thing can be from another thing without being of the same nature.  The prepositions de and ex both signify a material cause and an efficient cause, but only de signifies that the cause and its effect are consubstantial. While Christ is the only natural Son of the Father, God has many adopted children. The Evangelist distinguished these two types of sonship by specifying that the Son of God is born of the Father (de Patre), whereas God’s adopted children are spiritually born from God (ex Deo).