Isaiah 35:4 Say to those with fearful hearts, “Be strong, do not fear; your God will come, he will come with vengeance; with divine retribution he will come to save you.”
Micah 15:5 I will execute vengeance in anger and fury on the heathen, such as they have not heard.
Revelation 19:11-21 describes the ultimate war with Christ, the conquering commander who judges and makes war “with justice” (v. 11). It’s going to be bloody (v. 13) and gory. The birds will eat the flesh of all those who oppose Him (v. 17-18). He has no compassion upon His enemies, whom He will conquer completely and consign to a “fiery lake of burning sulfur” (v. 20).
http://www.gotquestions.org/war-Bible.html