This faith has everything to do with trust in the God who has already proven to be trustworthy. When you pray there has to be some recount of what God has done already. First of all, this type of faith Jesus is referring to is not for salvation but for accessing heaven’s power. So when he say, “have faith in God” it encompasses a logic that, “if yo already seen what he can do, keep your faith their.” See, its evident in the text because Peter sees and acknowledges what happens, “how did it wither?”
