What does Isaiah 1:5 mean?
The Lord pauses His case against Israel to ask a question: Why do you keep doing these things? Why keep acting in ways that lead to consequences and punishments?The question can be taken in two ways. First, the Lord wants Israel—specifically the southern tribes of Judah—to understand why they will be struck down. When the blow comes, it will be because they have rebelled against Him. From another perspective, though, God seems to want Israel to face up to their reasons for continuing on the path that leads to destruction. This ruin is depicted later in the passage (Isaiah 1:7–8).
The Lord's answer to the question "why" seems to be that the people of Israel are spiritually sick. This error starts in the minds and continues to their hearts. Their heads are sick because their minds are closed to understanding that the Lord is the source of their survival and protection (Romans 12:2). Their hearts are faint, and weak, because they no longer trust Him (John 14:1).