And, then, in the Rock there is a spring, and round the spring there is 'the light of laughing flowers,' amidst the stern majesty of the cliff. Just as the Law-giver of old smote the rock, and there gushed out the stream that satisfied the thirst of the whole travelling nation, so Paul would have us Christians repeat the miracle by our faith. Of us, too, it may be said, they drank 'of that Rock that followed them, and that Rock was Christ.' Stable being, secure defence, a fountain of refreshment and satisfaction: all these blessings lie in that great metaphor. II. Now, note our plea with God, from what He is. 'Be Thou to me a Rock ... for Thou art a Rock.' Is that not illogical? No, for notice that little word, 'to me'--be Thou _to me_ what Thou art in Thyself, and hast been to all generations.' That makes all the difference. It is not merely 'Be what Thou art,' although that would be much, but it is 'be it to me,' and let _me_ have all which is meant in that great Name. But then, beyond that, let me point out to you how this prayer suggests to us that all true prayer will keep itself within God's revelation of what He is. We take His promises, and all the elements which make up His name or manifestation of His character to the world, whether by His acts or by the utterances of this Book, or by the inferences to be drawn from the life of Jesus Christ, the great Revealer, or by what we ourselves have experienced of Him. The ways by which God has revealed Himself to the world define the legitimate subjects, and lay down the firm foundation, of our petitions. In all His acts God reveals Himself, and if I may so say, when we truly pray, we catch these up, and send them back again to heaven, like arrows from a bow. It is only when our desires and prayers foot themselves upon God's revelation of Himself, and in essence are, in various fashions, the repetition of this prayer of my text: 'Be ... for Thou art,' that we can expect to have them answered. Much else may call itself prayer, but it is often but petulant and self-willed endeavour to force our wishes upon Him, and no answer will come to that. We are to pray about everything; but we are to pray about nothing, except within the lines which are marked out for us by what God has told us, in His words and acts, that He Himself is. Catch these up and fling them back to Him, and for every utterance that He has made of Himself, 'I am' so-and-so, let us go to Him and say 'Be Thou that to me,' and then we may be sure of an answer.