"And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ. Faithful is he that calls you, who also will do it."
Trusting Christ is God's call to us, so that He says, "Come unto me, all you that labor and are heavy laden, and I will give you rest" (Matt 11:28). Thus, the believer, being called to Him, comes. Then, God in Christ does EXACTLY what He is believed for. He doesn't say, "Come unto me, and make yourself rest", but He says that He'll do it, even as He sanctifies us completely (Matt 16:18).
Those who put salvation on God shall be saved, but people who trust themselves, even in the least, will find themselves UNFAITHFUL. We are like Reuben, Simeon, and Levi, whom the Lord found unfaithful and gave the blessing to Judah (Gen 49:3-12). It is the Lord Jesus' glory to deliver us, and He will not be helped. He will be trusted, and He will do the work Himself, as God has willed.
Having put salvation into His hands and glorified Himself in His goodness to sinners, God will not allow us to contribute. He works through faith, but faith looks back to Christ and relies on Him, not only for righteousness, but also for strength. God does the work according to His word, by His Son's blood, and by the power of the Spirit. We enjoy salvation, but we're saved by God and not by any contribution that we make.
I consider Paul, of whom it is written that he was the chief of sinners (I Tim 1:15). And, I look up to Christ in His faithfulness to me, and I say, "Why, Lord? Why such goodness to me", and I hear the same thing that Paul heard: "I have mercy on you because you are a sinner, and I will be glorified in helping you, so that others can see my greatness. Sinners will be encouraged by my goodness to you, so while you're the CHIEF of sinners, I will get glory in you, and I'll use you to encourage the brethren for whom I died." Thus, your and my sinfulness do not hinder the mercies of God; they make way for God to be glorified in delivering us from sin, changing us, and making us faithful by His longsuffering and kindness to us – (I Tim 1:17) "Howbeit for this cause I obtained mercy, that in me first Jesus Christ might show forth all longsuffering, for a [example] to them which should hereafter believe on him to life everlasting".
In Judges 20, Israel labored to defeat Benjamin, picturing our battle with sin. They fought the enemy twice with God's permission. He said, "Judah shall go up first", but twenty two thousand died (Judges 20:18, 21). Then, when asked, He said, "Go up against him", but eighteen thousand died this time (Judges 20:23, 25). And, this happened because He gave no promise. Israel was trying to overcome the enemy, even as we attempt to overcome sin, in their own strength. They had the command to go, even as the word of God continually commands us to holiness, but they hadn't yet trusted Christ for the victory, so they tried in vain on their own. Likewise, until we hear the gospel of God's grace to us in Christ Jesus, we cannot conquer our sins. But, when we hear Him say, "Go up; for tomorrow I will deliver them into your hand", then victory is sure (Judges 20:28). Faith isn't trusting ourselves; it is trusting Him. Trusting Christ for righteousness is trusting that His obedience is sufficient for God to justify you. Trusting His strength is believing that His strength is enough, when you and I have none. And, trusting His word is believing God IN SPITE OF every temptation to depart from Him. Every feeling and everything that seemingly contradicts His word is DISREGARDED for what is written, and in this, we please Him.
Therefore, salvation is God's work to perform, He shall do it, and we are to believe His faithfulness to the end. What He commands, both our perseverance and growth in grace, are His to perform, so that He is glorified and we're ambassadors of Christ, instead of ourselves. We don't thank God that we're unlike others and look down upon them. Instead, realizing that salvation is God's work, we look to Him to help others, even as He helped us for Christ's glory, our good, and to make us examples of His goodness to those who shall believe.