Terrible times, God says, are coming, and the proud will be caught in that time. If we want to be spared, if we want to be saved, if we want to witness these things and live eternally beyond it, then we must live by faith and wait for it. It will require perseverance and endurance.
The word translated as "faith" is not the normal Hebrew word for faith. It has a meaning more akin to "fairness": The just shall live by his fairness. By extension, we could say, he shall live by his stability, certainty, reliability, personal character, or integrity.
A person is faithful to God only because he trusts Him, and therefore, to help us to understand, the translators decided to insert the word "faith" here. Human faithfulness ultimately rests on his trust in God. If a person is going to be faithful, it is because he believes what God says, and he is motivated to have a genuine commitment to righteousness.
John W. Ritenbaugh
Faith (Part Two)