Romans 10:9-10, 16-18

because if thou shalt confess with thy mouth Jesus as Lord, and shalt believe in thy heart that God raised him from the dead, thou shalt be saved: for with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.

But they did not all hearken to the glad tidings. For Isaiah saith, Lord, who hath believed our report? So belief cometh of hearing, and hearing by the word of Christ. But I say, Did they not hear? Yea, verily, Their sound went out into all the earth, And their words unto the ends of the world.