We must overcome sin, which is the transgression of God’s Law. We must overcome as Christ overcame. How? By faith, God’s grace (Power). We are saved by grace through faith (Ephesians 2:8). Our faith in the power of God to deliver us from sin becomes our salvation. It is a gift to anyone who will accept it.
“Here is the patience of the saints: here are they that keep the commandments of God, and the faith of Jesus” (Revelation 14:12 KJV).
Galatians 2:15-16 KJV
 We who are Jews by nature, and not sinners of the Gentiles,  Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.
Christ warned us:
Revelation 3:2-3, 5 KJV
 Be watchful, and strengthen the things which remain, that are ready to die: for I have not found thy works perfect before God.  Remember therefore how thou hast received and heard, and hold fast, and repent. If therefore thou shalt not watch, I will come on thee as a thief, and thou shalt not know what hour I will come upon thee.  He that overcometh, the same shall be clothed in white raiment; and I will not blot out his name out of the book of life, but I will confess his name before my Father, and before his angels.
Revelation 2:7-10 KJV He that hath an ear, let him hear what the Spirit saith unto the churches; To him that overcometh will I give to eat of the tree of life, which is in the midst of the paradise of God.  And unto the angel of the church in Smyrna write; These things saith the first and the last, which was dead, and is alive;  I know thy works, and tribulation, and poverty, (but thou art rich) and I know the blasphemy of them which say they are Jews, and are not, but are the synagogue of Satan.  Fear none of those things which thou shalt suffer: behold, the devil shall cast some of you into prison, that ye may be tried; and ye shall have tribulation ten days: be thou faithful unto death, and I will give thee a crown of life.
Revelation 3:21-22 KJV
 To him that overcometh will I grant to sit with me in my throne, even as I also overcame, and am set down with my Father in his throne.  He that hath an ear, let him hear what the Spirit saith unto the churches.
Christ overcame by His faith and the Spirit of God (Power of God). Christ obeyed His Father, always. Christ believed His Father and lived the will of His Father by faith and God’s Spirit. We too will overcome as Christ lives in us via the Holy Spirit. God lived by faith and His Father’s Power. We live by faith and God’s Power.
Salvation belongs to God. He gives His gift unto us without charge if we accept it. It means that we agree to live the way of righteousness. When we accept God’s gift of salvation we are opened to the reality that is threefold: justification by faith, sanctification by faith, righteousness by faith. We will then be glorified as Christ was glorified of His Father.
Christ did not do it all for us, as if we need to do nothing but say we “believe” and “love” and go on living in sin, knowingly committing sin, and choosing to not change by not being changed: by not acknowledging our sin, by not repenting, by not forsaking all sin.
The only thing Christ did for us that we do not have to is this: He died the second death. He died for our sins. He paid the penalty for the sins we committed against Him. Period.
All is possible with God, but without God we can do nothing. It is by the grace (Power) of God that we live by faith. We have to choose. He does the work in us.