As Leviticus wraps up this section of statutes, rules and laws that make up the covenant between God and Israel, God already knows that Israel will break the covenant, and he warns them of the penalties that will come upon them when they do. He foreshadows all of the sorrows that would come upon the Israelites as a result of their disobedience and covenant-breaking. It's a horrifying list, and every one of them did come about later in Israel's history.
In this we see the mercy of God! He warned them in the beginning; he sent prophet after prophet to clearly tell them what would come and he begged them to turn from their evil ways, knowing that they would not. In our passage he says that even in their time of discipline, he will not spurn them or hate them or break his covenant with them, not because they deserve mercy, but because he is God.
How great is the faithfulness of our God, who keeps covenant with us even when we are faithless!
Thanks be to God for his unending mercy and grace!