The fact is familiar to all, that the Old Testament nowhere feels the necessity of proving the existence of God. That would have been a proof unintelligible to those to whom its prophets addressed themselves. In the time when the Old Testament came to him, man as little doubted the existence of God as he doubted his own life. But as life sometimes burned low, needing replenishment, so faith would grow despondent and morbid, needing to be led away from objects which only starved it, or produced, as idolatry did, the veriest delirium of a religion. A man had to get his faith lifted from the thoughts of his own mind and the works of his own hand, to be borne upon and nourished by the works of God,--to kindle with the sunrise, to broaden out by the sight of the firmament, to deepen as he faced the spaces of night,--and win calmness and strength to think life into order as he looked forth upon the marshalled hosts of heaven, having all the time no doubt that the God who created and guided these was his God. Therefore, when psalmist or prophet calls Israel to lift their eyes to the hills, or to behold how the heavens declare the glory of God, or to listen to that unbroken tradition, which day passes to day and night to night, of the knowledge of the Creator, it is not proofs to doubting minds which he offers: it is spiritual nourishment to hungry souls. These are not arguments--they are sacraments. When we Christians go to the Lord's Supper, we go not to have the Lord proved to us, but to feed upon a life and a love of whose existence we are past all doubt. Our sacrament fills all the mouths by which needy faith is fed--such as outward sight, and imagination, and memory, and wonder, and love. Now very much what the Lord's Supper is to us for fellowship with God and feeding upon Him, that were the glory of the heavens, and the everlasting hills, and the depth of the sea, and the vision of the stars to the Hebrews. They were the sacraments of God. By them faith was fed, and the spirit of man entered into the enjoyment of God, whose existence indeed he had never doubted, but whom he had lost, forgotten, or misunderstood. Now it is as such a minister of sacrament to God's starved and disheartened people that our prophet appears in ch. xl. 12-31.