ה֥וֹי אַשּׁ֖וּר שֵׁ֣בֶט אַפִּ֑י וּמַטֶּה־ה֥וּא בְיָדָ֖ם זַעְמִֽי׃
화 있을진저 앗수르 사람이여 그는 나의 진노의 막대기요 그 손의 몽둥이는 나의 분한이라
Midrash Tehillim
Another thing, "Arise, O Lord." Remember your oath that the angel swore in your name, as it says (Daniel 12:7), "And I heard the man clothed in linen, who was above the waters of the river, when he held up his right hand and his left hand unto heaven, and swore by Him that lives forever." And it is written (Isaiah 30:18), "Therefore the Lord will wait, that He may be gracious unto you." And all you have is an oath, as it says (1 Samuel 3:14), "Therefore I have sworn to the house of Eli." Rabbi Yehoshua ben Levi said in the name of Rabbi Levi, "The Holy One, blessed be He, said, 'I have made an oath to reveal the end and to redeem you. Even if Gog and Magog come, I will fight them,' as it says (Zechariah 14:3), 'Then the Lord will go forth and fight against those nations.'" Therefore, David said, "Arise, O Lord, let not man prevail," meaning, decide the matter in favor of merit rather than liability. Another interpretation is that the sword destroyed them, as it says (Psalms 20:9), "They are brought down and fallen, but we are risen, and stand upright." "Save my soul from the wicked, with Your sword." This was accomplished through the power of my forefathers and the power of the Torah, which is called a sword, as it says (Isaiah 49:2), "And He has made my mouth like a sharp sword." Another interpretation is that my soul was saved from that which was destined to come upon me through the power of that sword that Isaac said to me (Genesis 27:40), "And by your sword shall you live." Another interpretation is that it is the same sword with which you will descend in the world to come, as it says (Isaiah 10:5), "Woe to Assyria, the rod of My anger." Rabbi Yehoshua ben Levi said in the name of Rabbi Levi, "My soul was saved from that wicked one whom you will eventually defeat with your sword," as it says (Isaiah 34:5), "For My sword is sated in heaven."...
Midrash Tehillim
"You have given him the desire of his heart. And what is the permission of his lips? That when he says, "Let such and such a province rebel," his word is fulfilled, as he says, "Let Gobai go and destroy it" (Isaiah 10:6). Or if he says, "Let the Apharachites rebel against you," his word is fulfilled, as he says, "Let the angel of death go and destroy them" (ibid. verse 5). And his permission of his lips, when he decrees, his words are established."