In the tenth chapter of Romans, Paul explained as clearly as anywhere in the New Testament what is required for salvation. He began,
“The word is near you, in your mouth and in your heart” (that is, the word of faith which we preach): 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. (Romans 10:8–9)
The basis for salvation is the Word, and it has to be appropriated by faith. Then, there are two things we must do—one with the heart, one with the mouth. We have to believe with the heart, but we have to confess, or say it out, with the mouth. Paul went on,
For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation. (Romans 10:10)
You see? No confession, no salvation. It is good to believe in the heart, but belief alone is not sufficient. We must not only believe in our hearts, but we must also say it out boldly with our mouths, making the words of our mouths agree with the Word of God. Our initial confession relates us to Jesus as High Priest, but His ongoing ministry on our behalf as High Priest depends on our ongoing confession.