Thou art my God; I will exalt thee (comp. Exodus 15:2 and Psalms 118:28). To Isaiah the "Song of Moses" seems to have been a pattern thanksgiving, from which he delighted to draw his phrases when he was bent on formally singing praise to God.
Compare the following: Exodus 15:2 with Isaiah 12:2, "He is become my salvation;" the same with Isaiah 25:1, "He is my God; I will exalt him;" Exodus 15:6 with Isaiah 13:16, "Hath dashed in pieces;" Exodus 15:7 with Isaiah 47:14, "Consumed them as stubble;" Exodus 15:11 with Isaiah 46:5, "Who is like," etc.?
the same with Isaiah 25:1, "Doing wonders;" Exodus 15:16 with Isaiah 8:13, "Fear and dread;" Exodus 15:18 with Isaiah 24:23, "The Lord shall reign." Wonderful things; thy counsels of old are, etc.; rather, thou hast wrought wonders, counsels of old, faithfulness and truth.
The wonders for which God is praised were decreed in his counsels from all eternity; their accomplishment shows forth God's "faithfulness" and "truth."