This is cited in the Catechism of the Catholic Church thus:
1814 Faith is the theological virtue by which we believe in God and believe all that he has said and revealed to us, and that Holy Church proposes for our belief, because he is truth itself. By faith "man freely commits his entire self to God." For this reason the believer seeks to know and do God's will. "The righteous shall live by faith." Living faith "work[s] through charity."
The theme of the original words of the prophet Habakkuk (Hab 2:1-4) is persevering by faith (or faithfulness). Romans 1:17 uses these words to explain why the gospel is so important for faithful living: because the gospels reveal God's righteousness which encourages us (Rom 1:11-12) to be faithful. The righteous by faith in God naturally seek to know God's will, and this, the gospel reveals. But the word used in Hab 2:4 also means faithfulness, which extends faith into a faith that is lived. This necessarily places the faithful among those to whom the promise extends. Hab 2:3 tells us: 'For the revelation awaits an appointed time; it speaks of the end and will not prove false. Though it linger, wait for it; it will certainly come and will not delay.' Hebrews 10:37 phrases this wondrously: 'For yet "in a very little while, the one who is coming will come and will not delay"' -- linking the enduring confidence or trust of the faithful to the promised reward of salvation through Jesus Christ. And this saving faith is summed up in Gal 5:6 when St. Paul addresses the Christians who are reverting to Judaism and is emphasis on the Law, e.g., circumcision: 'For in Christ Jesus neiher circumcision nor uncircumcision counts for anything; the only thing that counts is faith working (or made effective) through love.'
Citations from Scripture:
|Gal 3:11 It is plainly written that no one becomes righteous, in God's way, by the Law: by faith the righteous shall live.|
|In the surrounding text (Gal 3:1-14), St. Paul is pointing out to Jewish converts, reverting to Judaism away from Christianity, that life is no longer to be had by observance of the Law, but through faith. Gal 3:12 says: 'Yet the Law gives no place to faith, for according to it: the one who fulfills the commandments shall have life through them.' Instead of trusting in what we do, we ought to have faith in God, and persevere in faithfulness.|
|Rom 1:17 This Good News shows us how God makes people upright through faith for the life of faith, as the Scripture says: The upright one shall live by faith.|
|In he surrounding text (Rom 1:16-17), St. Paul points out how the gospel, received by those who have faith, reveals the righteousness of God. He cites the faith (or faithfulness) of the righteous, as spoken of in Hab 2:4, perhaps to support the context of what he is preaching the gospel for: to strengthen the faith (and/or faithfulness) of the righteous. In both Romans 1:1-17 and Hab 2:1-4, note that the theme is encouraging us (Rom 1:11-12) to trust, patience and hope (Hab 2:3). It certainly is logical to view the gospel, the power of God for salvation, as crucial in encouraging the righteous, for in revealing to us God's righteousness, the gospel strengthens our faith. The theme of God's righteousness is prominent in the whole epistle to the Romans.|
|Hab 2:4 "I don't look with favor on the one who gives way; the upright, on the other hand, will live by faithfulness."|
|In the surrounding text (Hab 1:12-17, 2:1-5), the prophet Habakkuk complains to God about the oppression of his people. God replies that the oppression will end, with the upright persevering in a life of faithfulness.|
|Heb 10:38 Be patient in doing the will of God, and the promise will be yours. A little longer, a little longer -- says Scripture -- and he who is coming will come; he will not delay. My righteous one will live if he believes; but if he distrusts, I will no longer look kindly on him.|
|In the surrounding text (Heb 10:19-39), the message is an encouragement to trust in God and to persevere. Distrust is not an option (Heb 10:38, Hab 2:4 "the one who gives way")!|