"to do battle with it": and not to reduce it by hunger, thirst, or plague.
"then you shall call out to it for peace": Great is peace, for even in war peace is needed. Great is peace, for even the dead need peace. Great is peace, for even the dwellers on high need peace, as it is written (Iyyov 25:1) "He makes peace among His exalted ones." Great is peace, for the priestly blessing ends with "peace." And even Moses was a lover of peace, as it is written (Devarim 2:26) "And I sent messengers from the desert of Kedemoth … with words of peace."