In several places in Isaiah 43:11 to 52:11 (and I believe other places) he repeats phrases:
[Isa 43:11, 25 CSB] 11 "I -- I am the LORD. Besides me, there is no Savior. ... 25 "I -- I sweep away your transgressions for my own sake and remember your sins no more.
[Isa 48:11, 15 CSB] 11 "I will act for my own sake, indeed, my own, for how can I be defiled? I will not give my glory to another. ... 15 "I -- I have spoken; yes, I have called him; I have brought him, and he will succeed in his mission.
[Isa 51:9, 12, 17 CSB] 9 Wake up, wake up! Arm of the LORD, clothe yourself with strength. Wake up as in days past, as in generations long ago. Wasn't it you who hacked Rahab to pieces, who pierced the sea monster? ... 12 I -- I am the one who comforts you. Who are you that you should fear humans who die, or a son of man who is given up like grass? ... 17 Wake yourself, wake yourself up! Stand up, Jerusalem, you who have drunk the cup of his fury from the LORD's hand; you who have drunk the goblet to the dregs -- the cup that causes people to stagger.
[Isa 52:1, 11 CSB] 1 "Wake up, wake up; put on your strength, Zion! Put on your beautiful garments, Jerusalem, the Holy City! For the uncircumcised and the unclean will no longer enter you. ... 11 Leave, leave, go out from there! Do not touch anything unclean; go out from her, purify yourselves, you who carry the vessels of the LORD.
This might be taken as simply his literary style and to accentuate certain words and phrases but I'm wondering if he might be using it as a device to call attention to a theme of "double for all her sins - double comfort" in Isaiah 40:1-2:
[Isa 40:1-2 KJV] 1 Comfort ye, comfort ye my people, saith your God. 2 Speak ye comfortably to Jerusalem, and cry unto her, that her warfare is accomplished, that her iniquity is pardoned: for she hath received of the LORD'S hand double for all her sins.
Or is it an even wider theme? Or am I reading something into this?!