Charles H. Spurgeon on Psalms 105:41

He opened the rock, and the waters gushed out. With Moses' rod and his own word he cleft the rock in the desert, and forth leaped abundant floods for their drinking where they had feared to die of thirst. From most unlikely sources the all sufficient God can supply his people's needs; hard rocks become springing fountains at the Lord's command. They ran in the dry places like a river: so that those at a distance from the rock could stoop down and refresh themselves, and the stream flowed on, so that in future journeyings they were supplied. The desert sand would naturally swallow up the streams, and yet it did not so, the refreshing river ran "in the dry places." We know that the rock set forth our Lord Jesus Christ, from whom there flows a fountain of living waters which shall never be exhausted till the last pilgrim has crossed the Jordan and entered Canaan.