Right. My Torah says "You must not murder."
God has condoned killing before, and God has killed before. To say killing is not allowed at all is to say God has sinned. God does not sin. this means that, if God has used killing before, then killing is not completely wrong.
God hates hands that shed innocent blood (proverbs 6:17), and that would be classified as "murder". Killing is not always murder.
That being said, I'll leave you with a list that I wrote up for my friend a while back when she asked if I could provide her with scriptures that mentioned God supporting war:
Here are some scriptures dealing with war for you:
Numbers 2 “The tribes and Leaders of Armies”
God leading the Israelites to victory:
Exodus 17:8-16 (emphasis on 16)
Numbers 21: 1-3
Numbers 31:1-11
Numbers 33:50-56
Joshua 6
Joshua 8:1-2
Joshua 11:6-9, 16-23
Joshua 12
Judges 3: 9-10
Judges 3: 28-30
Judges 4: 23-24
Judges 7:19-25 God confuses the enemy and causes the enemy to kill themselves
Judges 8-21 basically more wars fought. The basic theme of Judges is Israelites sin, God delivers them into the hands of their enemies, Israelites repent, God raises up a judge for them who will lead them to a victorious war against their enemies, Israel delivered and serves God for a time, Israelites sin again, etc.
1 Samuel 15: 2-3
1 Samuel 17: 45-47
God using war to punish Israel:
Judges 3:12-13
Israel failing in war, because they fought without God’s blessing:
Numbers 14: 39-45
Joshua 7:1-9
1 Samuel 4
Of course, God does like treaties as well:
Joshua 9
End time prophecy:
Matthew 24: 6-7
During the 7 years of tribulation:
Revelations 6:3-4, 7-8
Revelations 19:19
And finally, peace will come after the Lord has returned and defeated Satan:
Isaiah 2:2-4
Micah 4:1-3
This doesn’t prove war is good or anything, because war isn’t a good thing, but it’s something we have to deal with in a sinful world until God returns and makes things right once more.