Literally, “Unless thou hast utterly rejected us,” unless “thou art very wroth against us.” This is stated as a virtual impossibility. God’s anger can be but temporary Psalms 30:5, and therefore the very supposition is an indirect expression of hope.
This verse speaks of the possibility of an utter rejection through God’s wrath. Therefore, to remove so painful a thought, and to make the book more suited for public reading, Lamentations 5:21 is repeated in many manuscripts intended for use in the synagogue. The same rule is observed in the synagogue with the two last verses of Ecclesiastes, Isaiah, and Malachi.