There are several views on how our salvation originated. I find most comfort in the view that makes salvation to be a work of God from beginning to end. Paul states in Ephesians 1:4 that God chose a people for Himself before He uttered a creative word. So our salvation began in eternity.
Then, as we read of the conversion experiences of people in the Scriptures, we see that the Bible portrays God as the One Who pursues, finds, and brings a people to Himself. For example, consider Lydia in Acts 16:14 (NIV) "One of those listening was a woman from the city of Thyatira named Lydia, a dealer in purple cloth. She was a worshiper of God. The Lord opened her heart to respond to Paul’s message."
We often pray that the Lord would open blind eyes to see the truth in Jesus, or we ask God to cause deaf ears to hear. Such prayers recognize that God is needed to begin the work of salvation in sinners' hearts.
Paul again puts it so clearly in Romans 3:11 (NIV) "...there is no one who understands; there is no one who seeks God." So when we see someone seeking the Lord, we can say that God has begun a good work in the seeker.
We can then say that God, Who began the work, will continue it until the day of Jesus Christ. Such truth is an enormous comfort to the Christian who is struggling with some sin that they cannot shake off. God is going to bring you through to victory. You cannot fall short of a full salvation.
The amazing truth in Romans 8:1-2 makes it clear that the law of God can never bring a person in Christ back under condemnation. "Therefore, there is now no condemnation for those who are in Christ Jesus, because through Christ Jesus the law of the Spirit who gives life has set you free from the law of sin and death." (NIV)
Those whom God has freed from the condemnation of the law can never be subject again to the law of God that says, "The soul that sins shall die."(Ezekiel 18:3). While the law of God shows a person in Christ that they have committed this sin or that, the law is silenced forever concerning condemnation. For the believer, the law speaks an instructive word but no longer a word of death.
Can your heart be lifted by this truth Christian? You have struggled to be free from some sin or other and you must continue to work toward victory because God is at work in you (Philippians 2:13). You shall prevail sooner or later.
Turn again in hope to the Lord. Remind him that it was He Who began the good work in you. Tell Him that you require and desire the strength to overcome the sin that dogs your heels. He will hear and come to provide you with all that is needed. The victory shall come and you shall soon rejoice in the strength of the Lord.