You have faith, because God says so.
Rom 12:3 .... according as God hath dealt to each man a measure of faith.

You cannot have faith unless you know how much God loves you.
(Ephesians 3:19) .... and to know the love of Christ which passeth knowledge, that ye may be filled unto all the fullness of God.

You cannot have faith unless you know God's promises to you.
Romans 9:4 They, (the righteous) are Israelites, God's adopted children. They have the Lord's glory, the pledges,* Moses' Teachings, the true worship, and the promises.
Galatians 3:16 The promises were spoken to Abraham and to his descendant. Scripture doesn't say, "descendants," referring to many, but "your descendant," referring to one. That descendant is Christ.

You cannot know God's promises to you unless you read His Word. When you read His Word, faith comes...
Romans 10:17 So then faith cometh by hearing, and hearing by the word of God.

When you pray, believe you have all things pertaining to life and Godliness, because God says so.
(2 Peter 1:3) ..... seeing that his divine power hath granted unto us all things that pertain unto life and godliness, through the knowledge of him that called us by his own glory and virtue;