Hebrews 10:19

Heb. 10:19. Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus,

Edwards connects this with Hebrews 10:22 and notes in "Concerning Faith":

3. Prayer is often plainly spoken of as the expression of faith. As it very certainly is in Romans 10:11-14, "For the Scripture saith, Whosoever believeth on him, shall not be ashamed. For there is no difference between the Jew and the Greek: for the same Lord over all, is rich unto all that call upon him, for whosoever shall call on the name of the Lord shall be saved. How then shall they call on him in whom they have not believed?" Christian prayer is called the prayer of faith, James 5:15. And believing is often mentioned as the life and soul of true prayer, as in the forementioned place. Matthew 21:21; Matthew 21:22; 1 Timothy 2:8, "I will that men everywhere lift up holy hands, without wrath and doubting." And Hebrews 10:19; Hebrews 10:22, "Draw near in full assurance of faith." James 1:5; James 1:6, "If any of you lack wisdom, let him ask it of God, that giveth to all men liberally and upbraideth not; and it shall be given him. But let him ask in faith, nothing wavering."

Heb. 10:20-21