You fight sin not by grit alone, but by reckoning yourself dead to sin and alive to God in Christ, and by walking in the Spirit. It is a battle of faith, winnable not because you are strong, but because He is.
Not a summary of these passages: the passages themselves. Read them, then come back to the study below.
The study
What the Scripture says
1
Fight from the identity Christ gave you
Our 'old self' was crucified with Christ so that we would no longer be slaves to sin. Paul tells us to 'consider yourselves also to be dead to sin, but alive to God in Christ Jesus our Lord' and not to let sin reign. The battle begins with who He has made you: a freed person, not a slave.
knowing this, that our old man was crucified with him, that the body of sin might be done away with, so that we would no longer be in bondage to sin.
Thus consider yourselves also to be dead to sin, but alive to God in Christ Jesus our Lord. Therefore don’t let sin reign in your mortal body, that you should obey it in its lusts. Neither present your members to sin as instruments of unrighteousness, but present yourselves to God, as alive from the dead, and your members as instruments of righteousness to God. For sin will not have dominion over you. For you are not under law, but under grace.
'Walk by the Spirit, and you won't fulfill the lust of the flesh.' By the Spirit we 'put to death the deeds of the body.' The battle is not sheer willpower but dependence: the Spirit produces love, joy, peace, and self-control as we stay in step with Him.
But I say, walk by the Spirit, and you won’t fulfill the lust of the flesh. For the flesh lusts against the Spirit, and the Spirit against the flesh; and these are contrary to one another, that you may not do the things that you desire.
But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faith, gentleness, and self-control. Against such things there is no law.
Paul is practical: 'Put to death therefore your members which are on the earth,' and name them. 'Put off' anger, wrath, and malice; 'put on' Christ and make no provision for the flesh. Vague dislike of sin changes nothing; a specific fight, by the Spirit, does.
Put to death therefore your members which are on the earth: sexual immorality, uncleanness, depraved passion, evil desire, and covetousness, which is idolatry;
We come to God as we 'draw near with boldness to the throne of grace, that we may receive mercy, and may find grace for help in time of need.' Where we are weak, His grace is sufficient, and He provides a way of escape in every temptation. The fight is fought in His strength, not ours.
Let us therefore draw near with boldness to the throne of grace, that we may receive mercy, and may find grace for help in time of need.
He has said to me, “My grace is sufficient for you, for my power is made perfect in weakness.” Most gladly therefore I will rather glory in my weaknesses, that the power of Christ may rest on me.
No temptation has taken you except what is common to man. God is faithful, who will not allow you to be tempted above what you are able, but will with the temptation also make the way of escape, that you may be able to endure it.
Jesus told His disciples to 'watch and pray, that you may not enter into temptation.' We confess our struggles to one another, bear one another's burdens, and stay sober and watchful against the enemy. Victory grows where a brother or sister fights beside us.
Watch and pray, that you don’t enter into temptation. The spirit indeed is willing, but the flesh is weak.”
Confess your offenses to one another, and pray for one another, that you may be healed. The insistent prayer of a righteous person is powerfully effective.
Brothers, even if a man is caught in some fault, you who are spiritual must restore such a one in a spirit of gentleness; looking to yourself so that you also aren’t tempted. Bear one another’s burdens, and so fulfill the law of Christ.
Be sober and self-controlled. Be watchful. Your adversary, the devil, walks around like a roaring lion, seeking whom he may devour. Withstand him steadfast in your faith, knowing that your brothers who are in the world are undergoing the same sufferings.
Thus consider yourselves also to be dead to sin, but alive to God in Christ Jesus our Lord. Therefore don’t let sin reign in your mortal body, that you should obey it in its lusts. Neither present your members to sin as instruments of unrighteousness, but present yourselves to God, as alive from the dead, and your members as instruments of righteousness to God. For sin will not have dominion over you. For you are not under law, but under grace.
Put to death therefore your members which are on the earth: sexual immorality, uncleanness, depraved passion, evil desire, and covetousness, which is idolatry;