Galatians 3
You foolish Galatians! Who has bewitched you? Before your very eyes Jesus Christ was clearly portrayed as crucified. 2 I would like to learn just one thing from you: Did you receive the Spirit by the works of the law, or by believing what you heard? 3 Are you so foolish? After beginning by means of the Spirit, are you now trying to finish by means of the flesh? 4 Have you experienced so much in vain—if it really was in vain? 5 So again I ask, does God give you his Spirit and work miracles among you by the works of the law, or by your believing what you heard? 6 So also Abraham “believed God, and it was credited to him as righteousness.
7 Understand, then, that those who have faith are children of Abraham. 8 Scripture foresaw that God would justify the Gentiles by faith, and announced the gospel in advance to Abraham: “All nations will be blessed through you. 9 So those who rely on faith are blessed along with Abraham, the man of faith.
10 For all who rely on the works of the law are under a curse, as it is written: “Cursed is everyone who does not continue to do everything written in the Book of the Law. 11 Clearly no one who relies on the law is justified before God, because “the righteous will live by faith. 12 The law is not based on faith; on the contrary, it says, “The person who does these things will live by them. 13 Christ redeemed us from the curse of the law by becoming a curse for us, for it is written: “Cursed is everyone who is hung on a pole.14 He redeemed us in order that the blessing given to Abraham might come to the Gentiles through Christ Jesus, so that by faith we might receive the promise of the Spirit.
Working out our own salvation gives you a reason to gloat before God and man; it give you a reason you boast about yourself, and what YOU did to get into heaven. Saying that it's up to you to work out your salvation means that Christ partially saved you, but you must carry the remaining burden of salvation (before your own savior), therefore voiding Ephesian 2:8-9, "For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— 9 not by works, so that no one can boast." We did noting to earn salvation, so therefore we don't have to live up-to some certain standard of holiness to keep it. The only thing we are told to do is to "Hold onto the profession of our faith." Or in other word, as long as don't willfully reject our salvation, there is nothing we can do that will cause us to be snatched out of the hands of God.