Jeremiah complains and accuses God because he is suffering. God responds to Jeremiah with assurance that He will restore him and protect him if Jeremiah simply chooses to return to God. God assures Jeremiah that God is his fortress; this is reminder for Jeremiah from earlier that He will make Jeremiah strong like walls. Walls are useless until tested; Jeremiah is now being tested through suffering. Jeremiah does end up choosing to return to the Lord in grace and he was restored to God's work