servant - in a collective sense, for the prophets in general, who foretold the return from Babylon; answering to “His messengers” (plural, in the parallel clause) [Maurer]. Antitypically, and ultimately, Messiah, who is the consummating embodiment of all the prophets and messengers of God (Mal 3:1; Mat 21:34, Mat 21:36, Mat 21:37; Joh 10:36); hence the singular, “His servant.”
counsel - predictions; prophets’ counsels concern the future (compare “counsellor,” Isa 41:28).
Jerusalem - regarded prophetically, as lying in ruins.