The best definitions of faith, by theologians of all schools, include the notion of insight, will, and affection. It is an act of the soul by which it looks at truth. But this act implies a desire to see and know the truth. Now, such an act as this lies at the root of all our knowledge, both of the material and spiritual world. How do I know the outward world? The passive exercise of sensation would never give such knowledge. The sights which enter the passive eye, the sounds which fill the passive ear, the feelings which affect the passive sense, give no real knowledge of outward things. That comes, not from sensation merely, but from sensation changed into experience by a voluntary activity. We must not only see, but _look_; not only hear, but _listen_; not only feel, but _touch_, in order to know. _Life_, therefore, the constant synthesis of these three elements,—life which, in every act, at once thinks, feels, and does,—alone gives us knowledge. Divorce _thought_ from affection and will, and let it act by itself, and it does not give knowledge; it only gives belief or opinion. Knowledge comes only from experience—and experience means communion. Communion with Nature by thought, desire, and action gives us the knowledge of Nature; communion with God by thought, desire, and act, gives us the knowledge of God. The organ by which we commune with God is faith; it includes the desire of knowing God, and the act of looking to him in order to know him. KNOWLEDGE of God, of immortality, and of spiritual things does not come from any process of reasoning on the one hand, nor from any single intuition of reason. Just so we do not know the material world by a process of reasoning on the one hand, or any single sensible perception on the other. _All knowledge comes from life_; or, as the apostle John expresses it, “Life is the light of man.” We become acquainted with outward nature by living processes—by repeated acts of sight, hearing, touch, taste. So we become acquainted with the spiritual world by repeated spiritual acts; by repeated processes of faith; by continued steps of devotion, submission, obedience, trust, love, prayer. In this way we come to _know_ God just as certainly, and just in the same way, as we know things visible or things audible.