One of the cornerstone beliefs of the New Testament is “Salvation by faith and not by works.” Jesus truly paid all the price to redeem us from our sins on the cross and now by faith believing in His finished work on the cross we have a way to salvation. Rom 10:9-10 says, “that if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved. v10 for with the heart one believes unto righteousness, and with the mouth confession is made unto salvation.” There are two very important parts in this passage: 1) confess – (To concede, admit, confess; of sins. Hence, to confess publicly, acknowledge openly, profess). What are we to confess- the Lord Jesus. The word Lord is His title like in our country governor or president. Lord means master. We are to confess our sins and that Jesus is now the master of our lives (no longer ourselves). 2) believe – (to have faith in or upon, to entrust) that Jesus died for our sins, but also God the Father raised him from the grave on Sunday morning showing His acceptance of Jesus payment for our sins to give us eternal life with Him when we pass from this life. Jesus now lives in those who have confessed and believed in the form of the Holy Spirit which will not leave us until we step over into heaven. So you see it is not just hearing a story how Jesus died for our sins and then we pray a short prayer for forgiveness. It is a life altering experience where we no longer live for ourselves but for Him.
One of the main reasons that the Book of James in the New Testament was written is to help us understand that when a person comes to Christ he is a new person and now his life is different because God now lives in him. Read slowly and think about James 1:21-27.
21 Therefore lay aside all filthiness and overflow of wickedness, and receive with meekness the implanted word, which is able to save your souls.
22 But be doers of the word, and not hearers only, deceiving yourselves. 23 For if anyone is a hearer of the word and not a doer, he is like a man observing his natural face in a mirror; 24 for he observes himself, goes away, and immediately forgets what kind of man he was. 25 But he who looks into the perfect law of liberty and continues in it, and is not a forgetful hearer but a doer of the work, this one will be blessed in what he does.
26 If anyone among you thinks he is religious, and does not bridle his tongue but deceives his own heart, this one's religion is useless. 27 Pure and undefiled religion before God and the Father is this: to visit orphans and widows in their trouble, and to keep oneself unspotted from the world.
Also James 2:14-26
14 What does it profit, my brethren, if someone says he has faith but does not have works? Can faith save him? 15 If a brother or sister is naked and destitute of daily food, 16 and one of you says to them, "Depart in peace, be warmed and filled," but you do not give them the things which are needed for the body, what does it profit? 17 Thus also faith by itself, if it does not have works, is dead.
18 But someone will say, "You have faith, and I have works." Show me your faith without your works, and I will show you my faith by my works. 19 You believe that there is one God. You do well. Even the demons believe — and tremble! 20 But do you want to know, O foolish man, that faith without works is dead? 21 Was not Abraham our father justified by works when he offered Isaac his son on the altar? 22 Do you see that faith was working together with his works, and by works faith was made perfect? 23 And the Scripture was fulfilled which says, "Abraham believed God, and it was accounted to him for righteousness." And he was called the friend of God. 24 You see then that a man is justified by works, and not by faith only.
A person that is truly a Christian, his/her life will be different. They will have the power of the Holy Spirit to live for God and become more and more like Him.
We are not saved by our good works, but we prove our salvation by our good works.