Commentaries:
Neither circumcision nor uncircumcision is of any great importance in terms of conversion, the way of God. What is important is that there is a new creation. This verse, then, is really neither for nor against circumcision. It is only saying that what matters is whether a person has been divinely transformed into a morally new and different person. In that, there is great spiritual benefit, a new creation.
John W. Ritenbaugh
Pentecost and the Holy Spirit
Some had taught the Galatian Christians that "Gentile" Christians should become physically circumcised. Paul disagrees. He makes it plain that the real motive of those teaching this doctrine is to "make a good showing of the flesh . . . that they may not suffer persecution for the cross of Christ" (Galatians 6:12; 5:11; I Corinthians 7:19; Romans 2:28-29). In verse 15, he asserts that "neither circumcision nor uncircumcision avails anything, but the new creation." Paul reiterates what he says in Galatians 5:6: What is important is a walk of "faith working through love." Upon those who so walk, the apostle concludes, will be "peace and mercy" (verse 16).
Physical descent - whether one is a Gentile or an Israelite - matters nothing. What matters is whether a person is nurturing the new man, once established by God, through a renewal process which involves walking in His law.
Charles Whitaker
Choosing the New Man (Part Two)
In Galatians 6:12-16; Ephesians 2:10-18; and Colossians 3:9-11, Paul broaches the subject of circumcision. He often connects the new man with circumcision because he understands the symbolism behind circumcision, and so should we.
When practiced according to God's law, the ritual of circumcision pertains to men, that is, males, taking place on the eighth day after parturition. Eight is the number of "new beginnings," the idea being that seven is the number of perfection, and seven plus one - eight - restarts the cycle. Thus, the eighth day of the week is Sunday, in reality the beginning of the new week. The Last Great Day, which occurs eight days after the Feast of Tabernacles begins, looks forward to the day when God will make all things new. This is the important symbolic message behind physical circumcision: The boy - the man - circumcised on the eighth day is a "new man."
However, the new man of whom Paul speaks is not new because of physical circumcision. He is new because he has obeyed God's command to "circumcise the foreskin of [his] heart, and be stiff-necked no longer" (Deuteronomy 10:16, see Jeremiah 4:4). Paul, understanding this, claims that "circumcision is that of the heart, in the Spirit." "Heart," of course, refers to mind. The new man is new because he is "renewed in the spirit of [his] mind" (Ephesians 4:23). By definition, the new man is spiritually circumcised - circumcised in his mind.
Charles Whitaker
Choosing the New Man (Part Two)
Walk according to this rule means "understand and apply this principle."
After Jacob's name was changed to Israel, through the centuries Israel gradually became a code name for the called and chosen of God who had made a covenant with Him. Here in Galatians 6, that code name is transferred openly and clearly to the church, and Paul attaches the prepositional phrase "of God" to show possession to differentiate it from the physical nation also named "Israel." God is creating a new nation—a New Covenant people—whose citizenship is in heaven and whose people owe their loyalty to the Kingdom of God, its laws, and its purposes.
The Israel of God—the remnant, the elect, the vessels of mercy, the children of promise—is a spiritual body, the Body of Jesus Christ (Colossians 1:18). There is neither Jew nor Greek, male nor female. In one sense, there is no nationality, for we are being transformed into a new "nationality"—the Kingdom of God! God is doing a new thing.
John W. Ritenbaugh
The Covenants, Grace, and Law (Part Eleven)
The ritual itself does not change a person's heart, as it has no power to do so. However, what really avails, what is really important, is "a new creature," that is, a new creation: a person who is then born of God.
John W. Ritenbaugh
The Covenants, Grace, and Law (Part Twenty-Eight)
Other Forerunner Commentary entries containing Galatians 6:15:
Galatians 6:12-16
Ephesians 2:10-18
Colossians 3:9-11