Deuteronomy 20

v1-9: When the Israelites went to war against their enemies they could find encouragement in “the presence of God with them,” and His promise to give them victory them. “Those who have God with them have no reason to fear.” Pastors and elders today are to encourage Jesus’ followers “in their spiritual conflict with the world and the sinful nature, and to assure them that they are conquerors—in fact, more than conquerors—through Christ who loved us.”

v10-20: God would be just if He were to quickly destroy sinners, "yet because he takes no pleasure in destroying them, he declares peace and begs them to be reconciled." But if those who He offers peace to "reject his offer and do not accept its benefits in time, then judgment will triumph over mercy in carrying out the punishment as much as mercy now triumphs over judgment in salvation."

Deuteronomy 21

v1-9: The ceremony described would teach Israel "to work as hard as they possibly could to prevent, discover, and punish murder," and to "instil in people a fear of the guilt of shedding blood." In the church today, the process of church discipline for unrepentant sin is to produce in members "a righteous anger" at sin and "fear" of sinning themselves.

v10-14: The actions of the woman in shaving her head, trimming her nails, and changing her clothes "represented putting aside her sinful way of life," and was "a sign that the woman had abandoned idolatry" and now worshipped the Lord. It should be evident from the way we live that we have put our trust in Christ to save us.

v15-17: "If we want to live quiet but full lives, then we should observe God's law rather than satisfy our own immoral desires."

v18-23: "If this law was carried out properly" in Israel as a nation, "it would early destroy the wicked of the land. It would prevent the cancer from spreading by promptly cutting out the diseased part, for those who were bad members of families would never make good members of a community." Jesus was thought to be a rebellious son and experienced the curse of the law. But it is us who are rebellious, not Him, "which shows how great his love was" that He would take this punishment for us.