The scripture quotation in this verse comes from Psalm 143.2, with one significant addition: by doing what the Law requires. This phrase (literally “works of the Law”) has reference to those things done in obedience to the Law and which may be looked upon in themselves as a means of establishing one in a right relationship with God.

Put right (in God’s sight) renders the same verb that was used in 1.17. It will be further discussed in 3.24. Once again Paul reminds his readers that the purpose of the Law is not to give men salvation, but to make them know that they have sinned.

The basic relationship in the first part of verse 20 is that of result and means. By doing what the Law requires is the means of the first part of the sentence, though in a sense it is not the means, since no man is by this means put right in God’s sight. This relationship may be expressed in some languages as “just because a man does what the Law requires does not mean that he is put right with God.” In some languages this may be expressed as a condition—for example, “If a man does what the Law requires, that still does not mean that he is put right with God.”

Since the second part of verse 20 is in contrast with the first, it may be necessary to introduce some adversative particle such as “but,” “rather,” or “on the other hand”—for example, “rather, the Law causes men to know that they have sinned.”

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on Paul’s Letter to the Romans. (UBS Handbook Series). New York: UBS, 1973. For this and other handbooks for translators see here .