Prepositions are important.
“We are saved BY grace THROUGH faith.” This verse doesn’t tell us we are saved by our faith but by His grace. We appropriate this grace (Titus 2:11-12) in our lives by putting our faith in the Lord Jesus Christ. When we do this, we are acquitted as innocent in the eyes of God.
”By faith.” From the time of Abraham God has always accepted faith in lieu of good deeds and credited it to a believer’s account as ‘righteous’ (Gen. 15:6; Rom. 4:5).
What is faith? Is it just a mental assent? No, faith is something we do. In Hebrews 11 God shows us the faith of the saints in the Old Testament. All of them revealed their faith by doing something. Noah built an ark. Abraham left his home. Joshua marched around the walls of Jericho. Rahab hid the Israelite spies. Faith is not something declared in words, such as in creeds but cannot be demonstrated – faith is to trust and obey. Faith is practiced in deeds. “I will show you my faith by what I do,” said James.
As with salvation, faith is an ongoing thing according to the Bible. Faith is a continuous attitude expressed in action. If you believe in someone, do you do it just for a moment? This is silly, but many teach this when it comes to Christ. One moment of faith secures them forever, so they say. If you truly believe in someone, you will go on trusting (and obeying) them, no matter what the situation.
‘By faith’ means persistent faithfulness. “The righteous shall live by faith” (Heb. 10:38) Our salvation begins with faith and ends with faith, that is, if we continue in faith (Col. 1:23).
“… receiving the end of your faith—the salvation of your souls.” (1 Peter 1:9)