Faith Comes From Hearing:

  So faith comes from hearing...and hearing by the word of Christ.  Romans 10:17

  But Did They Believe and Heed the Glad Tidings?  Romans 10:14-16

  Believe that Jesus is:

The Son of God
God With Us
The Christ

  Believe in the Gospel:

"And after there had been much debate, Peter stood up and said to them, "Brethren, you know that in the early days God made a choice among you, that by my mouth the Gentiles should hear the word of the gospel and believe." Acts 15:7 (NAS)