What is the righteousness which is of faith?
The righteousness which is of faith is the righteousness that comes by virtue of believing the word of God. It is not obtained by works of the law, but is described as the word of faith that is preached, near in the mouth and in the heart.
Les explains that the righteousness which is of faith is the righteousness that comes by believing the word of God. This contrasts with the righteousness of the law under Moses, which was legalism and required works, yet still had to have faith; works without faith could never amount to anything and God will not accept them. Les then points to verse 6, where this righteousness of faith speaks, saying not to ask in the heart who shall ascend into heaven to bring Christ down, or who shall descend into the deep to bring Christ up from the dead. Instead, the word is near, in the mouth and in the heart, that is, the word of faith which is preached.
But the righteousness which is of faith speaketh on this wise, Say not in thine heart, Who shall ascend into heaven? (that is, to bring Christ down from above:)