You remember when these words were spoken. Christ had knelt to wash the disciples' feet. Peter, in penitence and self-reproach, had hesitated to permit this lowly service of Divine love. But Christ answered by revealing the meaning of His act as a symbol of the cleansing of the soul from sin. He reminded the disciples of what they knew by faith,--that He was their Saviour and their Lord. By deed and by word He called up before them the great spiritual truths which had given new meaning to their life. He summoned them to live according to their knowledge, to act upon the truth which they believed. I am sure that His words sweep out beyond that quiet upper room, beyond that beautiful incident, to embrace the whole spiritual life. I am sure that He is revealing to us the secret of happy living which lies at the very heart of His gospel, when He says: If ye know these things, happy are ye if ye do them. i. "If ye know,"--there is, then, a certain kind of knowledge without which we can not be happy. There are questions arising in human nature which demand an answer. If it is denied we can not help being disappointed, restless, and sad. This is the price we have to pay for being conscious, rational creatures. If we were mere plants or animals we might go on living through our appointed years in complete indifference to the origin and meaning of our existence. But within us, as human beings, there is something that cries out and rebels against such a blind life. Man is born to ask what things mean. He is possessed with the idea that there is a significance in the world beyond that which meets his senses. John Fiske has brought out this fact very clearly in his last book, Through Nature to God. He shows that "in the morning twilight of existence the Human Soul vaguely reached forth toward something akin to itself, not in the realm of fleeting phenomena, but in the Eternal Presence beyond." He argues by the analogy of evolution, which always presupposes a real relation between the life and the environment to which it adjusts itself, that this forth-reaching and unfolding of the soul implies the everlasting reality of religion. The argument is good. But the point which concerns us now is simply this. The forth-reaching, questioning soul can never be satisfied if it touches only a dead wall in the darkness, if its seeking meets with the reply, "You do not know, and you never can know, and you must not try to know." This is agnosticism. It is only another way of spelling unhappiness. "Since Christianity is not true," wrote Ernest Renan, "nothing interests me, or appears worthy my attention." That is the logical result of losing the knowledge of spiritual things,--a life without real interest, without deep worth,--a life with a broken spring. But suppose Renan is mistaken. Suppose Christianity is true. Then the first thing that makes it precious, is that it answers our questions, and tells us the things that we must know in order to be happy.