Faith is based on knowledge, the "knowledge of God" referred to in Scripture, the knowledge that Jesus came to reveal when the time was ripe: the true and complete "face" of God. So that by knowing Him we may come to believe in Him, and by believing in Him we may enter a fellowship or communion which consists also in hoping in, and, most importantly, loving Him.
We believe because this God, demonstrated by everything Jesus said and did from the beginning of his life on earth through His passion, death, and resurrection is proven to be incomparably trustworthy, good, merciful: to have an uncompromising love for mankind. Jesus gives us something to believe in. And grace then enables that faith to actually take root and express itself as we come to accept and embrace that gift, even if only weakly at first. This direct and intimate knowledge that begins in this life and is to be fully realized in the next is referred to in Jer 31:34:
"No longer will they teach their neighbor,
or say to one another, ‘Know the Lord,’
because they will all know me,
from the least of them to the greatest,”
declares the Lord."
And John 17:3:
"Now this is eternal life: that they know you, the only true God, and Jesus Christ, whom you have sent."