Acts 8:36  And as they went on their way, they came unto a certain water: and the eunuch said, See, here is water; what doth hinder me to be baptized? 
Acts 8:37  And Philip said, If thou believest with all thine heart, thou mayest. 

Rom 10:9  That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.