Gazing upon Jesus is the answer for weary and fainthearted fighters of sin:
Heb. 12:1 Therefore, since we are surrounded by such a huge crowd of witnesses to the life of faith, let us strip off every weight that slows us down, especially the sin that so easily trips us up. And let us run with endurance the race God has set before us. 2 We do this by keeping our eyes on Jesus, the champion who initiates and perfects our faith. Because of the joy awaiting him, he endured the cross, disregarding its shame. Now he is seated in the place of honor beside God’s throne. 3 Think of all the hostility he endured from sinful people; then you won’t become weary and give up.