Charles Spurgeon Commentary Jeremiah 4:1-2

"If thou wilt return, O Israel, saith Jehovah, if thou wilt return unto me, and if thou wilt put away thine abominations out of my sight; then shalt thou not be removed; and thou shalt swear, As Jehovah liveth, in truth, in justice, and in righteousness; and the nations shall bless themselves in him, and in him shall they glory." — Jeremiah 4:1-2 (ASV)

So he sets before them life and death. First, he begins with these words of encouragement. He begs them to come, for God is willing to receive them despite all.