Exodus 15:16
Fear and dread shall fall upon them; by the greatness of thine arm they shall be as still as a stone; till thy people pass over, O LORD, till the people pass over, which thou hast purchased. Fear and dread shall fall upon them; by the greatness of thine arm they shall be as still as a stone; till thy people pass over, O LORD, till the people pass over, which thou hast purchased.
The verse is part of the song of triumph and praise sung by the whole host of Israel, ringing out after God opened a path through the Red Sea, brought His chosen people safely through to the farther shore, and drowned and destroyed Pharaoh's pursuing Egyptian army while Israel praised Him. It belongs to Israel's praise for that deliverance and to the triumph over it, recalling the Red Sea deliverance when God overcame Egypt and brought Israel safely through. At the sea Israel's leader was Jesus Christ present in the pillar of cloud, and God's protection ensured that no Israelite perished. Moses was commanded to preserve the song so Israel could teach its children about God's past dealings.
Its meaning is that fear and dread fall on Israel's enemies, who by the greatness of God's arm and power are left motionless and still as stone until the people He has purchased pass over by. At the sea this was fulfilled in the pursuing Egyptians, who were made afraid and unable to stop Israel from passing through safely. Their fear and dismay as the waters closed over them shows the terror that fell on enemies, while Israel reached safety on the farther shore and celebrated God's power keeping them safe in escape. Looking forward, the surrounding peoples and nations Israel would meet on the way to Canaan would be overcome with fear at God's power and remain still as stone while His redeemed people passed through and onward to the promised land, with their safe passage an act of His strength and protection. Sung together as the people journeyed through the wilderness, the song fixed precious lessons in their minds, lifted thoughts from trials and difficulties of the way, soothed and calmed the restless turbulent spirit, implanted principles of truth in the memory, strengthened faith, taught order and unity by concert of action, and brought the people into closer touch with God and with one another.