Romans 3:3

What if some did not believe? had not faith in God, and as a consequence of their unbelief were unfaithful to God; for both these ideas are included in the original word.

Shall their unbelief; their unbelief and unfaithfulness to God's covenant with them, but which, as the apostle has taught, they lost its benefits and brought upon themselves the wrath of God, "who will render to every man according to his deeds." Chap Romans 2:6.

Make the faith of God without effect? annul God's faithfulness in fulfilling the terms of his covenant with Abraham and his seed? The unbelieving Jews thought that God's covenant with their fathers bound him to bestow upon them eternal life, irrespective of their own conduct, and that a failure to do this would be a violation of the divine faith. The apostle, having shown that circumcision and the other privileges of the covenant can profit only those who are faithful to its conditions, and that the unfaithful Jew will be condemned along with the Gentiles, rejects with horror the idea that this is an annulling of the divine faithfulness.