Again, creation language is used to describe God’s victory as being final, pictured in the words, you trampled the sea with your horses.
The sea is a reference to the Babylonian nation who will be stood upon by God’s mighty power. As a warrior seated on his horse, God is described as riding victoriously into battle.
His defeat of the Babylonians is described as the surging of mighty waters.
This is a reference to the receding of the waters of the Red Sea that covered the Egyptian soldiers and brought their mission to an end. The entire Egyptian army was wiped out by the water that fell upon them. They will not be able to withstand the might of God but will fall at his hand.
15 You trampled the sea with your horses, the surging of mighty waters.