In part 1 of my observations of this passage in Habakkuk, I suggested that the common interpretation drawn from this text and the places where Paul quotes it does not bring to light what the passage is trying to communicate. I mentioned how typical, protestant, evangelical explanations of this text have something to do with salvation, in that this passage in Habakkuk tells us “how” someone gets “saved.” I highlighted how this passage in Habakkuk sets at odds an already righteous person – who lives by “their faith” – with the wicked person – who lives by “their net.” As was stated previously as well, to inject the common interpretation into this passage would cause the passage to be redundant and not make any sense. It could read, “The righteous person, who is saved by their faith, is saved by their faith.”
The first place that we go wrong, if we interpret this passage in the typical fashion, is by erroneously pre-supposing that the verb “live” [יִחְיֶה; yich'eyee] in this passage is referring to acquiring “salvation,” in the traditional understanding of how one initially comes to receive salvation. To clarify, salvation from God is an act of the LORD’s grace through one’s faith/trust in him. I am not arguing about the “means” to salvation. What I am arguing for here is that this passage has more to do with the “means” to living the abundant life, which comes after the moment of salvation [John 10.10]. Hence, the person in this passage is already considered “righteous.”
After someone puts their trust in the LORD and is deemed “righteous,” they will then continue living and only truly “live” by walking in [their] faith[fulness] to YHWH. Paul says, “…for we walk by faith, not by sight” [2 Cor. 5:7]. In this context Paul is making known “the means” by which he is able to carry on and live – his faith. He does not walk by his sight; for if he did, then he would not be able “to live” the kind of life that God called him [and us] to live.
To make this more clear and practical for the believer, consider this example.
John is 25 and an unbeliever. He is introduced to the Gospel of God and receives the Lord Jesus. John is baptized shortly after that and begins attending a local church. His life bears fruit and everyone who knew him can readily see a change in him. No doubt, John is a Christian. Despite all the positive, immediate changes that have occurred in John’s life there still remains remnants of the “old” John. He still looses his temper at his wife every now and then, and some foul language slips out, too. The temptation and habit of browsing porn on the internet did not go away. John does not regularly feed himself God’s word, nor regularly spend time in prayer. John finds himself spending time with his old buddies, doing the same old things. Now, the minute John received Christ he was given two options on how to continue living – [1] according to the faith that he put in Jesus, [2] or the same way he had been living before. If John would have let his faith dwindle by not cultivated it by doing the things necessary in order to mature in his faith, he would have not been “living” by his faith. In other words, he would not have been experiencing the “abundant life” that Christ came to give. If John were to continue to seek God passionately, conform his life to the instructions found in God’s word, and surround himself with fellow believers who keep him accountable and whom John can confess sin to, then he would be truly “living” by “his faith.” John ["the righteous"] would then be experiencing the “abundant life” that one can have only by living according to their faithfulness to YHWH.
This is the essence of the Gospel of Christ – it is the call to embrace the “life” that God intended for his creation, which was made available by Christ’s life, death, and resurrection. This “life” is what Jesus called “abundant”; this “life” can only be experienced by our “faith[fulness]” to our Creator.
I call heaven and earth to witness against you today, that I have set before you life and death, blessing and curse. Therefore choose life, that you and your offspring may live, loving the LORD your God, obeying his voice and holding fast to him, for he is your life and length of days, that you may dwell in the land that the LORD swore to your fathers, to Abraham, to Isaac, and to Jacob, to give them. [Deuteronomy 30:19-20; italics mine]
For more on “righteousness” you might want to read this and this.