Jeremiah received another message from the Lord. He was to go to the gate of the temple in Jerusalem and deliver a prophecy in Yahweh"s name to the Judahites who entered to worship. This was probably the New or Eastern temple gate (cf. Jeremiah 26:10; Jeremiah 36:10). [source][source][source]
". . . during the pilgrimage festivals in the temple, the pilgrims were greeted at the temple gates by a servant of the institution, who asked them to examine their moral lives prior to passing through the gates and participating in the worship (see Psalm 15 , 24...). If Jeremiah assumed his role of "preacher at the gate" in an unofficial capacity, then it is possible that the custom had lapsed at that time (as seems entirely probable from the substance of the sermon) and was consciously resumed by the prophet to his own moral and spiritual ends." [1][source]