The waters saw thee. — Possibly alluding to the “look” which troubled the Egyptians (Exodus 14:24).
Were afraid. — Better, writhed, as in travail pains.
Went abroad — i.e., darted hither and thither. The arrows are the lightnings.
Related Commentaries of Psalms 77:16
Psalms 77:16
16 The waters saw thee, O God, the waters saw thee; they were afraid: the depths also were troubled.