What does Habakkuk mean when he says, “The righteous will live by his faith” (2:4)? How does Paul use this verse in Romans 1:17?
The first half of Habakkuk 2:4 addresses the posture of an unrighteous soul; It speaks of it: “Behold, his soul is puffed up; it is not upright within him.” His soul being puffed up, and the second phrase describing that soul not being upright within is establishing the unregenerate status of this soul. It is proud, thinking itself highly capable but in reality condemned. In typical Hebrew poetic fashion, a parallelism is employed that contrasts this negative with a positive to bring greater clarity; namely, the 2nd half of verse 4 which defines what it means to be upright in God’s sight. The opposite of pride is the meekness of faith. Faith is what the righteous, what the upright soul lives by…not in a puffed-up-self-made posture, but in humility.
Paul uses this verse to wage war against the idea of works righteousness, against the idea that a soul can be upright before God apart from faith in Christ. Paul’s usage in Roman’s 1:17 is paramount to his entire letter to the Romans as he labors to teach why not all Israel received Christ and why the gentiles are coming in. Faith alone reveals God’s righteousness. Not puffed up pride, or good works, but faith in Christ which produces humility and leads to truly good works. So Paul teaches the church to live by faith, living in it in an all encompassing way, thus ever warning the brothers to beware of those walking in pride, or of the temptation to think they can be righteous apart from Christ.