It's interesting you bought up the character of God in relation to murder. For God murdered many of the people who lived in Jericho by making their homes in the walls fall down crushing the inhabitants. The rest who survived were killed by Joshua's army as commanded by God. Now 40 years earlier God commanded His people, including Joshua, 'Do not kill' thus expressing love and kindness instead. This would be in line with God's character would you say? It appears that this same God revealed His same character (love and kindness) when He gave them the land He had promised to give them. But this time He said, 'do kill'. Kill everything that has breath, men, women, children and animals. And the God of Abraham, Isaac and Jacob Who promised you this land will join in on this killing on mass. God will cause walls to fall and crush people, He will send large hailstones and destroy others. Josh 10:11 And it happened, as they fled before Israel and were on the descent of Beth Horon, that the Lord cast down large hailstones from heaven on them as far as Azekah, and they died. There were more who died from the hailstones than the children of Israel killed with the sword.
So are you saying that the end (the manifestation of God’s character) justifies the means (kill or do not kill)? So what is sin, to kill or not kill?