Rashi

For the Lord has poured upon you, etc. (נָסַךְ) an expression of mixing wine. Comp. (Prov. 9: 2) “She mixed (מָסְכָה) her wine.” It may also be an expression of princedom (נְסִיכוּת). He caused a spirit of deep sleep to overcome you, (lit., to rule over you). Concerning the transgressors of Israel he was prophesying, for they were stargazers and were experts in adjuring the heavenly princes, each one with the proper name for adjuring him. Therefore, they say, “Who will encamp upon us (Jer. 21:13)? If the enemy comes upon us, we can make for it a wall of fire around, ([Most manuscripts read:] If the enemy comes upon the city, we can make for it a wall of fire around,) or surround it with the Great Sea.” Said the Holy One, blessed be He, “I will change the heavenly princes; the one appointed over fire, is appointed over water. When he adjures the prince of fire to bring him fire, he will reply, “This is not mine,” And, likewise, the prince of water. And even the name by which you adjure him, he does not recognize. This is the closing of the eyes and the covering of the heads of the stargazers.