Comentario citado sobre Isaías 12:5

כי גאה גאה FOR HE IS GLORIOUSLY SUBLIME — render this as the Targum does: for He is exalted above all exalted beings and real exaltation (supremity) is His alone. [Another explanation: the repetition of the word is intended to state that He has done something which it is impossible for a human being (lit., flesh and blood) to do. When he (the latter) fights against another and vanquishes him he throws him off the horse, but here — horse and its rider together hath He hurled into the sea. The usage is, that in the case of everything which cannot possibly be done by anyone except Him the appropriate expression to use is a form of the root גאה, as in (Isaiah 12:5), “for He hath done גאות” — gloriously. In the same way you will find that throughout the whole Song the words are repeated: (v. 2) “The strength and vengeance of the Lord have become my help”; (v. 4). “The Lord is a man of war, the Lord is His name” (cf. Rashi’s explanation of this), and this is the case in all the verses]. Another explanation of כי גאה גאה: I will sing unto the Lord although (כי) He is exalted high above all songs and however much I may praise Him there will still remain something additional in Him to be praised (עוד יש בו תוספת — I can never exhaust his praises), and not as is the practice in respect to a human king whom one praises, attributing to him certain virtues whilst these are really not in him (cf. Mekhilta).