We humans are unique and distinguish ourselves from the rest of creation in that we speak, that we can communicate and verbally express ideas, feelings and thoughts, and, perhaps more than we sometimes understand, also create with our words.
[the ki bit ends here (: ]
All people have a treasure, something that they store up, in their hearts, and the Bible says that out of the abundance of the heart the mouth speaks.
Romans 10:10 says,
"For it is with your heart that you believe and are justified, and it is with your mouth that you confess and are saved".
That was how you and I came to Jesus. Regardless of circumstances, time, if we were alone or with others, at some point we started believing with our heart, not with our brains. You could say that our heart was filled with a kind of assurance.
The treasure in our heart became so full that it started flowing out of our mouths. Both these things are needed: the faith of the heart and the confession of the mouth.
When they come together, the result is salvation.