Galatians 4:6

And because ye are sons, God sent forth the Spirit of his Son into our hearts, crying, Abba, Father. So that thou art no longer a bondservant, but a son; and if a son, then an heir through God.

Some scholars read the first clause, "as proof that ye are sons";[11] but Sanday believed it is better to retain it as in the English Revised Version (1885),[12] showing that the time of receiving the gift-ordinary of the Holy Spirit is subsequent to achieving the status of sonship and a consequence of it. This is without doubt the true meaning, for it coincides with the promise of the apostle Peter (Acts 2:38) that the reception of the Holy Spirit is to be expected after faith, repentance and baptism into the name of Christ, and as a promise to be fulfilled subsequently to such faith and obedience. That is why Paul also referred to the same gift as "the Holy Spirit of promise" (Ephesians 1:13).

Whereby we cry, Abba, Father ... (KJV) indicates that one of the fruits of the Holy Spirit in Christian hearts is the sense of nearness to God, indicated by the prayers addressed to God in such terms of intimacy, "Abba" being the ordinary word used by Hebrew children in addressing their father. However, it is ridiculous to equate this word with the English word "Daddy," which in current usage has lost a lot of the reverential respect which pertained to the Aramaic word, "Abba."

No longer a bond servant, but a son ... The world, at least that portion of it which accepts Christianity, has come of age in Christ. The idols, liturgical externals, pageantry, regalia and all other visible external spectacularism of pagan worship are not merely unnecessary, but destructive of genuine worship and service of Christ.

If a son, then an heir through God ... A Christian is not an heir of Abraham, but an heir with him, by virtue of sonship and union with Christ. The reason Paul stressed God's Fathership of the Lord Jesus Christ in Galatians 4:4 was correctly discerned by Pink who declared that "God must be the Father of the Lord Jesus Christ, in order to be the God and Father of his people whom he chose in Christ."[13] The Christian's sonship to God is derived from his unity with Christ, identity with Christ, as being "in Christ," and thus a part of that spiritual body which "is Christ," who is truly and actually the sinless and perfect Son of God.

[11] William Barclay, The Letters to the Galatians and Ephesians (Philadelphia: The Westminster Press, 1954), p. 38.

[12] William Sanday, Ellicott's Commentary on the Holy Bible (Grand Rapids, Michigan: Zondervan Publishing House, 1959), p. 450.

[13] Arthur W. Pink, Gleanings from Paul (Chicago: Moody Press, 1967), p. 93.