Your past failures may bring you down, but God can still use you to do things that can require great faith:
Luke 5:1-11: (1)And it came to pass, that, as the people pressed upon him to hear the word of God, he stood by the lake of Gennesaret, (2) And saw two ships standing by the lake: but the fishermen were gone out of them, and were washing their nets. (3) And he entered into one of the ships, which was Simon’s, and prayed him that he would thrust out a little from the land. And he sat down, and taught the people out of the ship. (4) Now when he had left speaking, he said unto Simon, Launch out into the deep, and let down your nets for a draught. (5) And Simon answering said unto him, Master, we have toiled all the night, and have taken nothing: nevertheless at thy word I will let down the net. (6) And when they had this done, they inclosed a great multitude of fishes: and their net brake. (7) And they beckoned unto their partners, which were in the other ship, that they should come and help them. And they came, and filled both the ships, so that they began to sink. (8) When Simon Peter saw it, he fell down at Jesus’ knees, saying, Depart from me; for I am a sinful man, O Lord. (9) For he was astonished, and all that were with him, at the draught of the fishes which they had taken: (10) And so was also James, and John, the sons of Zebedee, which were partners with Simon. And Jesus said unto Simon, Fear not; from henceforth thou shalt catch men. (11) And when they had brought their ships to land, they forsook all, and followed him.