Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; by which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; and that he was buried, and that he rose again the third day according to the scriptures: and that he was seen of Cephas, then of the twelve: after that, he was seen above five hundred brethren at once: of whom the greater part remain unto this present, but some are fallen asleep. After that he was seen of James; then of all the apostles. And last of all he was seen of me also, as one born out of due time.
---1 Corinthians 15:1-8
This gospel must be believed in the heart and not simply the head.
For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.
Many have confessed with the mouth, who have not believed in the heart, that Jesus is Lord and Savior of all. We must do both, or perish. That is why Jesus said,
Ye must be born again.
If we believe in our hearts, we have a ready confession of it. Scripted confessions on Sunday morning avail nothing. A confession of faith is always on my tongue if Jesus is in my heart. And He is. Is Jesus in your heart? I pray He is!