The mountains saw thee, and they trembled: the overflowing of the water passed by: the deep uttered his voice, and lifted up his hands on high.
The mountains saw thee - even as God, with his, all-searching glance, "beheld" and "measured" them.
And they trembled - repetition, with increased emphasis, of some of the tremendous phenomena mentioned in Habakkuk 3:6.
The overflowing of the water passed by - namely, of the Red Sea, and again, of the Jordan. God marked his favour to His people in all the elements, causing every obstacle, whether mountains or waters, which impeded their progress, to pass away (Calvin). Maurer, not so well, translates, 'torrents (rains) of water rush down.' х Zerem (H2230) mayim (H4325) `aabar (H5674) agrees best with the English version-literally, 'the inundation of waters passed by.']
The deep uttered his voice, and lifted up his hands on high - "His hands" mean its billows lifted on high. Personification. As men signify by voice or gesture of hand that they will do what they are commanded, so these parts of nature testified their obedience to God's will (Exodus 14:22, "The waters were a wall unto them (the Israelites) on their right hand and on their left;" Joshua 3:16; Psalms 77:17-18; Psalms 114:3-7, "The sea saw it, and fled; Jordan was driven back. The mountains skipped like rams ... What ailed thee, O ... sea, that thou fleddest? thou Jordan, that thou wast driven back? ... Tremble, thou earth, at the presence of the Lord, at the presence of the God of Jacob").