Midrash sa Isaias 41:4: Ein Yaakov (Glick Edition), Mekhilta DeRabbi Yishmael, Sifra & Esther Rabbah

(Fol. 4b) MISHNA IX: He (R. Akiba) was wont to say: "The father influences his son in beauty, force, wealth, wisdom, longevity, and the reward to be bestowed on [his] posterity; and herein lies the end of destiny, as it is said (Is. 41, 4) He predetermines from the beginning of fate of the generations to come, (Fol. 5) and though it is said (Gen. 16, 13) They will enslave them and torture them for four hundred years, yet there is another passage (Ib. 16) The fourth generation will return again unto here."

"the L–rd is a man of war': What is the intent of this? Because He revealed Himself at the sea as a hero waging war — "The L–rd is a man of war" — and He revealed Himself at Sinai as an elder full of mercy, viz. (Exodus 24:10) "And they saw the G–d of Israel … and under His feet as the work of a sapphire brick and as the appearance of the heavens in brightness" [[ see Rashi], and (Daniel 7:9) "I watched as thrones were set up, and the Ancient of Days sat … (10) A stream of fire was flowing forth from before Him, etc." — So as not to give a pretext to the peoples of the world to say that there are two (i.e., numerous) deities, (it is written) "The L–rd is a man of war — the L–rd is His name. It was He upon the sea, He in Egypt, He in the past, He in the future, He in time to come, He in this world, He in the world to come. As it is written (Devarim 32:39) "See, now, that it is I, I, and there is no god with Me, etc.", and (Isaiah 41:4) "Who wrought and did? The Caller of the generations (into being) from the beginning. I, the L–rd, was the first (to perform wonders and to help,) and it is I (who will be) with (you,) the later (generations."

"I am the L–rd your G–d who took you out of the land of Egypt." What is the intent of this? Because He appeared at the Red Sea as a hero waging war, viz. (Exodus 15:3) "The L–rd is a Man of war," and at Mount Sinai, as an elder full of mercy, so as not to provide an opening for the nations of the world to say that there are two Deities, (He said) "I am the L–rd your G–d." It was I at the Red Sea, and it is I on the dry land. It was I in the past and it will be I in time to come. I in this world and I in the world to come. As it is written (Devarim 32:39) "See, now, that I, I am He," (Isaiah 46:4) "And until you grow old, it is I," (Ibid. 44:6) "Thus said the L–rd, the King of Israel, and its Redeemer, the L–rd of hosts: I am first and I am last," and (Ibid. 41:4) "Who wrought and did, the caller of the generations from the beginning? I, the L–rd, am first, and with the last it will be I."