One cannot even begin to “live by faith” while “dead in trespasses and sins” (Ephesians:2:1), which is mankind’s natural condition. One must be made “alive from the dead” (Romans:6:13) by receiving God’s forgiveness in Christ. The Christian life of faith is only for those who are “in the faith” (2 Corinthians:13:5). Living “a good Christian life” is not the way to become a Christian. Only those who already are Christians can live that life. Nor is it lived in order to earn heaven, which is impossible, but out of gratitude to Christ for having paid the penalty for sin.
A Christian has been “born again” of the Spirit of God (John:3:3-8) through “the Word of God” (1 Peter:1:23) by believing the gospel (Romans:1:16) and is a “new creature” (2 Corinthians:5:17) in Christ, having been “created in Christ Jesus unto good works, which God hath before ordained that we should walk in them” (Ephesians:2:10). If we trust Him to do so, surely God will open the right doors, guide each step of every Christian’s life, and provide the means of fulfilling the “good works” that He has ordained for each of us.
Clearly, one must first enter upon the Christian life by faith in Christ in order to begin to “live by faith.” Paul exhorts us, “As ye have therefore received Christ Jesus the Lord, so walk ye in him” (Colossians:2:6). And how did we receive Christ? As helpless, hopeless sinners who could do nothing for our own salvation but had to look entirely to Christ to save us. In that same attitude of unworthiness and complete dependence upon God for His grace and upon Christ to live His life through us, we live by faith the Christian life.