Galatians 4:6

6.And because ye are sons. The adoption which he had mentioned, is proved to belong to the Galatians by the following argument. This adoption must have preceded the testimony of adoption given by the Holy Spirit; but the effect is the sign of the cause. In venturing, he says, to call God your Father, you have the advice and direction of the Spirit of Christ; therefore it is certain that you are the sons of God. This agrees with what is elsewhere taught by him, that the Spirit is the earnest and pledge of our adoption, and gives to us a well-founded belief that God regards us with a father’s love.

“Who hath also sealed us, and given the earnest of the Spirit
in our hearts.” (2 Corinthians 1:22.)

“Now he that hath wrought us for the self-same thing is God,
who also hath given unto us the earnest of the Spirit.”
(2 Corinthians 5:5.)

But it will be objected, do not wicked men, too, carry their rashness so far as to proclaim that God is their Father? Do they not frequently, with greater confidence than others, utter their false boasts? I reply, Paul’s language does not relate to idle boasting, or to the proud opinion of himself which any man may entertain, but to the testimony of a pious conscience which accompanies the new birth. This argument can have no weight but in the case of believers, for ungodly men have no experience of this certainty; as our Lord himself declares.

“The Spirit of truth,” says he, “whom the world cannot receive, because it seeth him not, neither knoweth him.”
(John 14:17.)

This is implied in Paul’s words, God hath sent forth the Spirit of his Son into your hearts. It is not what the persons themselves, in the foolish judgment of the flesh, may venture to believe, but what God declares in their hearts by his Spirit. The Spirit of his Son is a title more strictly adapted to the present occasion than any other that could have been employed. We are the sons of God, because we have received the same Spirit as his only Son.

Let it be observed, that Paul ascribes this universally to all Christians; for where this pledge of the Divine love towards us is wanting, there is assuredly no faith. Hence it is evident what sort of Christianity belongs to Popery, since any man who says, that he has the Spirit of God, is charged by them with impious presumption. Neither the Spirit of God, nor certainty, belongs to their notion of faith. This single tenet held by them is a remarkable proof that, in all the schools of the Papists, the devil, the father of unbelief, reigns. I acknowledge, indeed, that the scholastic divines, when they enjoin upon the consciences of men the agitation of perpetual doubt, are in perfect agreement with what the natural feelings of mankind would dictate. It is the more necessary to fix in our minds this doctrine of Paul, that no man is a Christian who has not learned, by the teaching of the Holy Spirit, to call God his Father.

Crying. This participle, I think, is used in order to express greater boldness. Hesitation does not allow us to speak freely, but keeps the mouth nearly shut, while the half-broken words can hardly escape from a stammering tongue. “Crying,” on the other hand, expresses firmness and unwavering confidence.

“For we have not received again the spirit of bondage to fear,
but of freedom to full confidence.” (Romans 8:15.)

Abba, Father. The meaning of these words, I have no doubt, is, that calling upon God is common to all languages. It is a fact which bears directly on the present subject, that the name Father is given to God both by the Hebrews and by the Greeks; as had been predicted by Isaiah,

“Every tongue shall make confession to my name.”
(Isaiah 45:23.)

The whole of this subject is handled by the apostle at greater length in his Epistle to the Romans. I judge it unnecessary to repeat here observations which I have already made in the exposition of that Epistle, and which the reader may consult. Since, therefore, Gentiles are reckoned among the sons of God, it is evident that adoption comes not by the merit of the law, but by the grace of faith.