The Christian life has always included struggles against sin. Even the Apostle Paul wrestled with this (Rom. 7:15). We understand that our sin natures are not completely cast aside until we die or the Lord returns, and thus we are still capable of disobedience. This does not absolve us of the responsibility to do God’s will, however, and certainly does not preclude God from delivering us from our sins.
In 1 Peter 4:1-2, Peter puts an interesting spin on our fight against the sin nature: “Therefore, since Christ has suffered in the flesh, arm yourselves also with the same purpose, because he who has suffered in the flesh has ceased from sin, so as to live the rest of the time in the flesh no longer for the lusts of men, but for the will of God.” Peter’s point appears to be that when we take on the sufferings of Christ (contextually, persecution for the faith), we cease from sin precisely because suffering sharpens our focus—the things of the world fade quickly under such circumstances.