Again, an understanding of the material conditions under which life is lived, greatly helpful to the preacher as it is, is not all that is needed. The messenger must know in what direction runs the _thought_ of his age. The learned and able authorities dwelling within the covers of the precious volumes upon his library shelves form an interesting and inspiring society in which it is pleasant to spend his hours. The religious people with whom the preacher mostly consorts form a more, or less, agreeable circle in which it may be pleasant to pass such time as he can spare for social enjoyment. But the world has many men and many minds. Continually the ferment of intellect goes on. Thoughts ripen into tendencies with wonderful rapidity. It is recorded of a great emperor that he was wont to disguise himself and wander at large among his people, listening to the talk of common men. As a result he knew, even before his counsellors, how set the wind. Hence he was "beforehand" in his government. There is no rebellion that is not first a conspiracy, and no conspiracy that is not first a smouldering, and then a blazing, discontent. The preacher must hearken beneath the eaves for his people's sake. He must stand sentinel upon the tower. He must be a watchman in the night. He must put his ear to the earth that he may detect the far-off tramp of approaching foes. What is being said in a whisper to-day will be cried from every high place to-morrow, and he who listens to the whisper may be found ready to answer or explain the cry--perhaps, even, to prevent it. "As those who watch for your souls," so writes the Apostle. "_As those who watch._" Behold the shepherd, as he tends the flock, sleeplessly gazing for the approach of lion, or wolf, or bear, or prowling Bedouin of the desert. So must the preacher sweep the horizon by day; so listen to the speaking silences of the night. Then to all this the messenger must add an intimate knowledge of the Church, of her condition and of her needs. To know her history is well. It is knowledge from which the Christian worker of every name may derive many warnings. It will be found to contain many lessons profitable for consolation and for inspiration. It will suggest many an useful explanation of phenomena in the church life of to-day. But the preacher must study the Church as she is in this very hour. How beat her pulses _now_? How run the currents of her life in the days that _are_? Does her faith wax, or wane? Does her love grow colder or warmer with the passing years? Is it well with her, or is it ill?