God showed grace without compromising the value of human life when He provided the cities of refuge for those who committed manslaughter. John Calvin comments that the “temporary exile [of the one guilty of manslaughter] clearly showed how precious human blood is in the sight of God.” When we do not support appropriate penalties for the taking of human life, we show disdain for other people and for the Lord in whose image we are made.
Theonomists want to establish the penalties of the Mosaic law in society today, but this position is ultimately not tenable because unlike the old covenant, the new covenant community is not a geopolitical entity. That does not mean, however, that lawmakers should not consider the Mosaic code at all when writing legislation. In fact, society as a whole would benefit if the principles in the Law (what we call today “natural law”) were applied more often.