These words are taken from a passage in which Amos illustrates prophecy from other instances of his shepherd life. We have seen what a school of vigilance the desert is. Upon the bare surface all that stirs is ominous. Every shadow, every noise--the shepherd must know what is behind and be warned. Such a vigilance Amos would have Israel apply to his own message, and to the events of their history. Both of these he compares to certain facts of desert life, behind which his shepherdly instincts have taught him to feel an ominous cause. _Do two men walk together except they have trysted?_--except they have made an appointment. Hardly in the desert, for there men meet and take the same road by chance as seldom as ships at sea. _Doth a lion roar in the jungle and have no prey, or a young lion let out his voice in his den except he be taking something?_ The hunting lion is silent till his quarry be in sight; when the lonely shepherd hears the roar across the desert, he knows the lion leaps upon his prey, and he shudders as Israel ought to do when they hear God's voice by the prophet, for this also is never loosened but for some grim fact, some leap of doom. Or _doth a little bird fall on the snare earthwards and there be no noose upon her?_ The reading may be doubtful, but the meaning is obvious: no one ever saw a bird pulled roughly down to earth when it tried to fly away without knowing there was the loop of a snare about her. Or _does the snare itself rise up from the ground, except indeed it be capturing something?_--except there be in the trap or net something to flutter, struggle and so lift it up. Traps do not move without life in them. Or _is the alarum trumpet_[153] _blown in a city_--for instance, in high Tekoa up there, when some Arab raid sweeps from the desert on to the fields--_and do the people not tremble?_ Or _shall calamity happen in a city and Jehovah not have done it? Yea, the Lord Jehovah doeth nothing but He has revealed His purpose to His servants the prophets._ My voice of warning and these events of evil in your midst have the same cause--Jehovah--behind them. _The lion hath roared, who shall not fear? Jehovah hath spoken, who can but prophesy?_[154] We cannot miss the personal note which rings through this triumph in the reality of things unseen. Not only does it proclaim a man of sincerity and conviction: it is resonant with the discipline by which that conviction was won--were won, too, the freedom from illusion and the power of looking at facts in the face, which Amos alone of his contemporaries possessed.