“and they went into the land of Egypt.” They had always intended to go to Egypt (Jer. 41:17). Because of that, even though they had agreed to obey the voice of Yahweh whether His direction was something they wanted or did not want (Jer. 42:6), when Jeremiah opposed their plan they called him a liar (Jer. 43:2) and went to Egypt anyway.
“the voice of Yahweh.” It was the prophet who did the speaking, but the “voice” was Yahweh’s voice.
“as far as Tahpanhes.” The Judeans did not go very far into Egypt. Tahpanhes was on the northern border of Egypt in the northeastern Nile delta. It was a fortress city that protected the northeastern border of Egypt. It is generally thought to be the same as the Greek city of Daphne.