John Wesley on Jeremiah 15:8

Their widows - The prophet still speaks of things to come as if present. In Jehoiakim's time we read of no such plenty of widows; they were multiplied when the city was besieged and taken in Zedekiah's time, to a great number, hyperbolically compared to the sands of the sea. The mother - Jerusalem was the mother of the Jewish people, against whom, Nebuchadnezzar the spoiler, at noon - day, was sent.