John Gill Commentary Jeremiah 39:2

"in the eleventh year of Zedekiah, in the fourth month, the ninth day of the month, a breach was made in the city,)" — Jeremiah 39:2 (ASV)

[And] in the eleventh year of Zedekiah, in the fourth month ,
&c.] The month Tammuz, which answers to part of June, and part of July: the ninth [day] of the month, the city was broken up ;
or taken by storm; the walls of it were broken by engines and battering rams, so that the Chaldeans could enter it, and take it. This was just a year and a half after it had been besieged, not being able to hold out any longer, because of the famine; see (Jeremiah 52:6Jeremiah 52:7) .