Christians should all have overcoming sin as one of our goals. Although we will never be perfectly victorious over sin in this life (1 John 1:8), we must recognize that overcoming sin is part of the battle which is the Christian life. God has not left us to battle sin on our own, however. He has given us clear instructions and several resources to aid in the struggle.
The first resource, and the most important, is the presence of the Holy Spirit in our hearts, without whom victory over sin is impossible. Not only must we have the presence of the Spirit, but we must also be "filled" with the Spirit in order to overcome sin (Ephesians 5:18-21). We should be so completely yielded to the Holy Spirit that He can possess us fully and, in that sense, fill us. Romans 8:9 and Ephesians 1:13-14 state that He dwells within every believer, but He can be grieved (Ephesians 4:30), and His activity within us can be quenched (1 Thessalonians 5:19). When we allow this to happen, we do not experience the fullness of the Spirit's working and His power in and through us. Therefore, the presence and the filling of the Holy Spirit are essential to overcoming sin.
Another resource God has given to us to overcome sin and live for Him is the Word of God, which is sufficient to equip us for every good work and to make us "complete" (2 Timothy 3:16-17). If it is able to make us complete, that would include the power to have victory over sin. Hebrews 4:12 tells us that the Word of God is living and powerful, able to penetrate straight to our hearts to root out and overcome the deepest sins of heart and attitude. Psalm 119:9 (NIV) refers to the power of the Word: "How can a young person stay on the path of purity? By living according to your word." Joshua 1:8further exhorts "This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success."
The Bible will help us to overcome sin, but not if it sits on the shelf until Sunday. We are to memorize it, meditate on it, or apply it to our lives. When it comes to the Word of God, we can't simply take in just enough to keep us alive spiritually. We must ingest enough of it to be healthy, thriving Christians, which involves feeding on it and meditating on its truths enough to derive its spiritual nutrition. The Bible is an essential and major part of the armor that God gives us to fight our spiritual battles (Ephesians 6:12-18). Without it, we have no hope of overcoming sin.
Prayer is the third crucial resource in our battle against sin. If Jesus had to pray diligently to prepare for the ordeal He was about to suffer, how much more do we who are weak and sinful have to rely on prayer to overcome temptation? In the Garden of Gethsemane, Jesus exhorted the disciples to "Watch and pray that you may not enter into temptation" (Matthew 26:41). When they failed to heed His warning, they fell into the sin of fear and unbelief (Mark 14:50). God has given us wonderful promises concerning prayer (Matthew 7:7-11; Luke 18:1-8; John 6:23-27; 1 John 5:14-15), and Paul includes prayer in his passage on preparing for spiritual battle (Ephesians 6:18). Prayer acknowledges that we recognize our own limitations and God's inexhaustible power and it allows us to tap into that power as we "approach God's throne of grace with confidence" (Hebrews 4:16 NIV) with our petitions and supplications.
A fourth resource in our war to conquer sin is the fellowship of other believers, particularly in the local church. Overcoming sin with the help and encouragement of others in love and good works (Hebrews 10:24) is much easier than going it alone. James tells us to confess our faults to one another (James 5:16) and pray for one another because just as iron sharpens iron, so one man sharpens another (Proverbs 27:17). There is strength and comfort to be found among a body of believers whose hearts are inclined toward God and one another (Ecclesiastes 4:11-12).
Accountability partners who can come alongside a struggling brother and render help in overcoming stubborn sins is another resource provided by the local church. Temptation is part of the Christian life (1 Corinthians 10:13), but God has promised not to test us beyond our ability to bear it and having an accountability partner or an accountability group can help us to overcome even the most stubborn of sins.
Sometimes victory over sin comes quickly; other times, victory comes more slowly. God has not left us helpless in our battle against sin. He has promised that as we make use of His resources, He will progressively bring about change in our lives. We can persevere in our efforts to overcome sin because we know that "The LORD is trustworthy in all he promises and faithful in all he does" (Psalm 145:13b NIV).