Not all men have faith. Therefore, any faith we have is God given. The only reason why our faith is creditted for anything is because of the One who gave it to us.
How does the fact that all men do not have faith equal that faith is God given?
Twice we are told that Jesus "marvelled" in the scriptures, and both times it concerned faith.
First, Jesus marvelled at the centurion's great faith.
Matthew 8
8 The centurion answered and said, Lord, I am not worthy that thou shouldest come under my roof: but speak the word only, and my servant shall be healed.
9 For I am a man under authority, having soldiers under me: and I say to this man, Go, and he goeth; and to another, Come, and he cometh; and to my servant, Do this, and he doeth it.
10 When Jesus heard it, he marvelled, and said to them that followed, Verily I say unto you, I have not found so great faith, no, not in Israel.
Why would Jesus marvel at the centurion's great faith if faith is given by God? Did he not know that his Father had given the centurion great faith? That makes no sense whatsoever.
Second, Jesus marvelled when his fellow countrymen did not believe.
Mark 6
1 And he went out from thence, and came into his own country; and his disciples follow him.
2 And when the sabbath day was come, he began to teach in the synagogue: and many hearing him were astonished, saying, From whence hath this man these things? and what wisdom is this which is given unto him, that even such mighty works are wrought by his hands?
3 Is not this the carpenter, the son of Mary, the brother of James, and Joses, and of Juda, and Simon? and are not his sisters here with us? And they were offended at him.
4 But Jesus said unto them, A prophet is not without honour, but in his own country, and among his own kin, and in his own house.
5 And he could there do no mighty work, save that he laid his hands upon a few sick folk, and healed them.
6 And he marvelled because of their unbelief. And he went round about the villages, teaching.
Why would Jesus marvel at his fellow countrymen's unbelief if faith is given by God? Did Jesus not know his Father had not given these people faith? This makes no sense at all.
These two passages make absolutely no sense whatsoever if faith is given to men by God. NONE.