Galatians 2:21

I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain.

I do not frustrate the grace of God - I do not make it void, as thou, Peter, art doing by Judaizing. In our I do not frustrate the grace of God - I do not make it void, as thou, Peter, art doing by Judaizing. In our justification three things go together; on God's part, His, grace; on Christ's part, the satisfaction of God's justice; on our part, lively faith in Christ's merits, ('Homily on Salvation, I.')

For - justifying the strong expression "frustrate,"

If righteousness, [ dikaiosunee (G1343)] - justifying and sanctifying (Romans 8:2).

Come by [ dia (G1223 )] the law. This asserts that the law is not a medium of righteousness; Galatians 3:11, that it is not the sphere [ en (G1722)] of righteousness; Galatians 3:21, that it is not the origin [ ek (G1537)] (Ellicott).

Is dead in vain, [ doorean (G1432)] - 'Christ died needlessly,' 'without just cause.' Christ's having died shows that the law has no power to justify us; for if the law can justify, the death of Christ is superfluous (Chrysostom).