“You shall set apart three cities for yourselves …” (v2). The “cities of refuge” in Israel were an acknowledgement that our human tendency toward anger and revenge can pervert justice and cause “innocent blood” to be shed (v6). While a proven case of intentional murder required the death penalty (v11-12), other situations were less clear, and the accused needed a safe place while the evidence was sorted out.
“Lest innocent blood be shed” (v10). God alone is perfectly just. Our own desire for justice must be tempered with humility as we recognize our limitations and work to protect the innocent.