I will give you an illustration. When I want light in my room I touch the electric button and the room is filled with light. The moment I press the button I expect the light will come, and I am surprised if it fails. Why? Touching the electric button is like the touch of faith; it brings us into contact with the source of light. Faith brings me into contact with God Himself, for He is the source of life and light. God has ordained that faith shall be a power as real and as uniform in its working as light or heat or electricity. Everything about them is a mystery which we do not fully understand, but all the same they are real to us and we use them. Although we do not understand them, yet we prove again and again that they supply us with new life and energy simply by a touch. Even a child can touch. Faith places all God's fulness at our disposal, but it is only according to our faith that we receive it. I know a poor woman who went through a time of great anxiety about her little girl who was ill. One day a Christian friend called to see her and she told her all about her trouble. When she had finished the friend said to her very tenderly, "You have forgotten one little word of five letters." "What is it? Do tell me," she exclaimed, looking puzzled. Then the friend, pointing on her five fingers, said slowly, _f-a-i-t-h_. The dark cloud cleared away and she was able to look up into God's face again and to trust Him. So when Christ says, "Have faith in God," it is a command to hold fast to God. It means trust God about everything, great and small; nothing is too small. Trust Him to save you, and to keep you. Trust Him in every difficulty and in every duty. "Little faith will bring your souls to heaven, but great faith will bring heaven to your souls." When Christ said to Peter and the others, "Have faith in God," He said it very earnestly and with a ring of deep conviction in His voice. He knew in Himself what dependence on God means in the earthly life. Day by day He showed what it is to have simple trust in God. When He said, "Have faith in God," He said it very solemnly, because He was speaking on behalf of His Father. He had come to reveal Him, so He says, "I do nothing of Myself, but as My Father hath taught Me I speak these things." He had already said, "He that believeth on Me hath everlasting life," and now He adds, "Have faith in God." Yes, He claims our confidence, our full confidence, not a half-hearted trust. Our Lord saw men seeking other objects of trust, so He says, "Take hold of God, hold fast to God, have faith in God and never let it go."