This is the second psalm in the Hallel. The first set forth the might and mercy of Jehovah. This is pre-eminently a song of His might, and so the name of God is used. If however it sings of His might, it sings of it as manifested in mercy. It is the song of the Exodus, and is full of beauty.
The first movement declares that the people passing out of Egypt, did so as the result of the presence of God. Among them was His sanctuary, and they were His dominion. Nature recognised His presence and obeyed His will. The sea fled, Jordan was driven back, mountains and little hills were moved. The singer asks the reason of this commotion, and without waiting for answer charges the earth to tremble at His presence.
Notice that this song includes the whole deliverance, the going out under Moses through the sea, and the going in under Joshua through Jordan. Again we imagine the great Leader about to accomplish His Exodus singing these words. Ere long all Nature would be convulsed as He passed out, and in breaking the way through for the oncoming hosts. It is possible in imagination to hear the thrill of triumph as the stately words so full of spiritual significance, sounded forth in that upper room.