John 1:12

But as many as received him
This is explained, in the latter part of the text, by believing in his name; for faith is a receiving him as the word, and Son of God, as the Messiah, Saviour, and Redeemer; a receiving grace out of his fulness, and every blessing from him, as a justifying righteousness, pardon of sin, and an inheritance among them that are sanctified; for though the generality rejected him, there were some few that received him:

to them gave he power to become the sons of God;
as such were very early called, in distinction from the children of men, or of the world; see ( Genesis 6:2 Genesis 6:4 ) . To be the sons of God is a very special favour, a great blessing, and high honour: saints indeed are not in so high a sense the sons of God as Christ is; nor in so low a sense as angels and men in common are; nor in such sense as civil magistrates; nor merely by profession of religion; much less by natural descent; but by adopting grace: and in this, Christ, the word, has a concern, as all the three divine persons have. The Father predestinated men to the adoption of children, secures this blessing for them in the covenant of his grace, and puts them among the children, and assigns them a goodly heritage: the Spirit, and who is therefore called the spirit of adoption, discovers and applies this blessing to them, and witnesses to their spirits that they are the children of God: and Christ, the word, or Son of God, not only espoused their persons, and in time assumed their nature, and by the redemption of them opened a way for their reception of the adoption of children; but actually bestows upon them the "power", as it is here called, of becoming the sons of God: by which is meant, not a power of free will to make themselves the sons of God, if they will make use of it; but it signifies the honour and dignity conferred on such persons: so Nonnus calls it, "the heavenly honour"; as indeed, what can be a greater? It is more honourable than to be a son or daughter of the greatest potentate on earth: and it is expressive of its being a privilege; for so it is an undeserved and distinguishing one, and is attended with many other privileges; for such are of God's household and family, and are provided for by him; have liberty of access unto him; are Christ's free men, and are heirs to an incorruptible inheritance. This is a privilege that excels all others, even justification and remission of sins; and is an everlasting one: and it also intends the open right which believers have unto this privilege, and their claim of it: hence it follows,

even to them that believe in his name;
that is, in himself, in Christ, the word: the phrase is explanative of the former part of the verse, and is a descriptive and manifestative character of the sons of God; for though the elect of God, by virtue of electing grace, and the covenant of grace, are the children of God before faith; and were so considered in the gift of them to Christ, and when he came into the world to gather them together, and save them; and so, antecedent to the Spirit of God, being sent down into their hearts, to make this known to them; yet no man can know his adoption, nor enjoy the comfort of it, or claim his interest in it, until he believes.