God did not heal Paul. He said to Paul that His grace was sufficient. I understand full well about faith. Faith is hope in the evidence that is unseen. Personally, I don't believe that anyone is in a position to demand anything from God, including healing.
Paul was not in need of a healing, but a Deliverance, and nowhere does God say to ask him for deliverance. He always said, you do it, you do the casting out.
He knew it was a messenger of Satan to buffet him, as he put it, and yet he still was asking God to take care of it for him.
When he sent out the disciples in twos, you didn't have them ask God to cast out those spirits, he told them to do it in his name. And that is how it works.
And when God said, my grace is sufficient for you, he wasn't saying, I'll sustain you with my grace while you suffer. He was saying, my grace was sufficient for you to receive salvation, my grace was sufficient for you to receive gifts of the Spirit, my grace was sufficient for you to cast out devils in other people, and so on and so forth. So again, he was saying you do it.
And if you are demanding the word of God be enforced, and demanding the devil take it's hands off you or someone else, then you are in essence, telling God what to do, seeing that the word of God IS God.
And concerning faith, you don't even understand what you're trying to quote.
Faith is the very thing one envisions.
Hope is in the future tense, as in, someday in the future. Whereas faith is in the now, as in, present tense, or even past tense. And if you look to the natural concerning your healing, as in nothing happening, then nothing will happen because you will believe what you are experiencing. Faith defies the present circumstances and logic.