It is sad that many professing believers can debate on biblical truths but yet do not really know how to be saved. Because knowledge (which is a change of mind) does not save but repentance (which is a change of heart).
Rom 10:9-10.
That if you confess with your mouth the Lord Jesus and believe in your heart that God raised Him from the dead, you will be saved. For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation.
Dr John MacArthur explained this way how to be saved in his book The Heart of the Bible :
“The first thing you must do is to confess with your mouth Jesus as Lord. This means more than acknowledging that Jesus is the Lord…After all, James 2:19 says that even demons know that God is the sovereign of the universe, but that knowledge does not save them.
Confessing Jesus as Lord means saying that Jesus is your Lord, your Sovereign. Making this confession means expressing out loud before others your deep personal conviction – without reservation – that Jesus is your Master and the Ruler of your life.
Jesus said, “If you want to follow Me, you must deny yourself.” (Luke 9:23). That is an amazing statement, considering the way people think about the role of Jesus in their lives today. The gospel is not about self fulfillment, as many suppose. It is about self denial. No one can confess Jesus as Lord and say, “OK, Jesus, I’m going to let you into my life and I want you to make me more successful and improve my marriage and lower my golf handicap.” The gospel is not about Jesus coming into your life and giving you what you want. It is about you coming before Jesus and saying, “God, be merciful to me, a sinner. Save me.” It is about saying, “Jesus, I acknowledge You as my Sovereign, Master, and Lord. I turn away from my own desires and my own need to control my life. I submit to whatever You want for me.”
The rich young ruler would not do that (Luke 18:18-27)…You aren’t saved by getting rid of your money. Jesus’ point was to test the man’s commitment to Jesus as his Lord. He could have asked him to do a hundred different things, but Jesus chose something He knew would test his willingness to deny himself. The ruler could not bring himself to submit to Jesus’ rule over him. He could not confess in this way that Jesus was Lord of his life. He went away sad – and unsaved.”