Galatians 2:21

“I do not frustrate the grace of God, etc..] Or “cast it away”, as the Vulgate Latin version reads it; or “deny it”, as the Syriac and Arabic; or “despise, reject, and make it void”, as other versions; meaning either the grace of the Son of God in giving himself for him, just mentioned by him; or the particular doctrine of grace, justification, he is speaking of, as proceeding from the grace of God, upon the foot of the righteousness of Christ; or the whole Gospel, all and each of which would be denied, despised, rejected, made null and void, be in vain, fallen and departed from, should justification be sought for by the works of the law: but this the apostle did not do, and therefore did not…”

“I do not frustrate the grace of God--I do not make it void, as thou, Peter, art doing by Judaizing. for--justifying the strong expression "frustrate," or "make void." is dead in vain--Greek, "Christ died needlessly," or "without just cause." Christ's having died, shows that the law has no power to justify us; for if the law can justify or make us righteous, the death of Christ is superfluous [CHRYSOSTOM]. Next: Galatians Chapter 3”

“I do not frustrate the grace of God - The word rendered “frustrate” (ἀθετῶ athetō) means properly to displace, abrogate, abolish; then to make void, to render null; Mark 7:9; Luke 7:30; 1 Corinthians 1:19. The phrase “the grace of God,” here refers to the favor of God manifested in the plan of salvation by the gospel, and is another name for the gospel. The sense is, that Paul would not take any measures or pursue any course that would render that vain or inefficacious. Neither by his own life, by a course of conduct which would show that it had no influence over the heart and conduct, nor by the observance of Jewish rites and customs, would he do anything to render that inefficacious.…”

“Meantime I do not make void - In seeking to be justified by my own works. The grace of God - The free love of God in Christ Jesus. But they do, who seek justification by the law. For if righteousness is by the law - If men might be justified by their obedience to the law, moral or ceremonial. Then Christ died in vain - Without any necessity for it, since men might have been saved without his death; might by their own obedience have been both discharged from condemnation, and entitled to eternal life. Next: Galatians Chapter 3”

“2:21 Perhaps Paul’s opponents in Galatia suggested that his message would make God’s grace to Israel meaningless, since it was connected with the law (cp. Rom 3:1-2, 31). Instead, it was Paul’s opponents who treated the grace of God as meaningless by voiding the need for Christ to die.”

“do not: Gal 2:18; Psa 33:10; Mar 7:9 \*marg. Rom 8:31 righteousness: Gal 2:16, Gal 3:21, Gal 5:2-4; Rom 10:3, Rom 11:6; Heb 7:11 Christ: Isa 49:4; Jer 8:8; Co1 15:2, Co1 15:14, Co1 15:17 Next: Galatians Chapter 3”