Romans 4:14

For if they that are of the law are heirs, faith is made void, and the promise is made of none effect: for the law worketh wrath; but where there is no law, neither is there transgression.

This is a continuation of the reasoning of the previous verse. The worldwide inheritance promised to Abraham was destined to be fulfilled in the singular seed, Jesus Christ, as indicated in Psalms 2:7,8 and Hebrews 1:2. Whiteside noted:

This promise of worldwide inheritance was not made to Abraham through the righteousness of the law, but through the righteousness of faith. Paul had shown the Judaizing teachers that Abraham was not righteous by law, but by faith. Now he shows briefly that the promise of the Messiah was through the righteousness of faith, and not through the righteousness of law.[13]

They that are of the law ... refers to persons who desired to be justified by keeping the Mosaic covenant, and more, wanted to bind it on the Gentiles as well. If keeping the law of Moses was the means of becoming heirs of God's promise, faith as a basis for it was voided. If the promise was merely to those who kept the law, the promise was ineffective, because no one ever did or ever could keep the law.

The law worketh wrath ... is but another way of saying that all anyone ever got out of keeping the law of Moses was condemnation, due to violation of it. The statement that there is no transgression where there is no law is an inverted way of saying that the only way to avoid human transgression (with its consequent condemnation) would be through having no law at all. Of course, this does not imply that there ever was a people who had no law. Also, Paul had already concluded Jews and Gentiles alike under sin.