Deuteronomy 20 raises lots of ethical questions for us. But it also contains the origins of of International Humanitarian Law and is designed to limit war and ensure peace.
In his novel The Plague, Albert Camus says that our common human experience is one of suffering and exile longing for love. Through Jesus' reconciling work on the cross, God brings us exiles home.
How do we respond to coronavirus? God's word tells us not to be afraid because he is with us. Nothing can separate us from his love in Christ. Free from fear we can serve our neighbours in love.