This from a sermon preached by C.H. Spurgeon from Mark 12:28-32.
There are others, too, who delight to spend time in contemplation. They believe in Jesus, in the Father, in the Spirit, they believe that there is but one God, and that these three are one. It is their delight to turn over the pages of revelation, as well as the pages of history. They contemplate God; he is to them a matter of curious study; they like to meditate upon him; the doctrines of his Word they could hear all day long. And they are very sound in the faith, extremely orthodox and very knowing, they can fight about doctrines, they can dispute about the things of God with all their hearts; but alas! their religion is like a dead fish, cold and stiff, and when you take it into your hand you say there is no life in it; their souls were never stirred with it; their hearts were never through into it. They can contemplate, but they cannot love; they can meditate, but they cannot commune; they can think of God, but they can never throw up their souls to him, and clasp him in the arms of their affections. Ah, to you, cold blooded thinkers — to you, this text speaks. Oh! thou that canst contemplate, but cannot love, — ”Thou shalt love the Lord thy God with all thy heart.”