The Lord is my strength and song. Literally, "My strength and song is Jah." The name Jah had not previously been used. It is commonly regarded as an abbreviated form of Jehovah, and was the form generally used in the termination of names, as Abijah, Ahaziah, Hezekiah, Zedekiah, Mount Moriah, etc.
It takes the place of "Jehovah" here, probably on account of the rhythm. He is become my salvation. Literally, "He has been to me for salvation," i.e; "He has delivered me out of the hand of Pharaoh and his host, and so saved me from destruction."
I will prepare him a habitation. This translation seems to have come originally from the Targum of Onkelos, who paraphrases the single word of the text by the phrase "I will build him a sanctuary." The meaning is a possible one: but most modern commentators prefer to connect the verb used with a root meaning "beautiful," and translate "I will glorify him."
(So Gesenius. Rosenmuller, Knobel, Kalisch, Cook. The LXX have δοξάσω. The Vulgate has glorificabo. The Syrian and Coptic versions agree, as do also the Targums of Jonathan and of Jerusalem.) The God of my father.
See the comment on Exodus 3:6.