One of the first things that God tells Noah after the flood is this.  Genesis 9:6 - “Whoever sheds man’s blood, by man shall his blood be shed, for in the image of God He made man.”

God is the one who first introduced to man to capitol punishment.  Anything that God originates MUST be good. 

James 1:17 - “Every good thing given and every perfect gift is from above…”

If EVERY good thing comes from God, it is impossible for any bad thing to come from Him.  It is against His character of being holy to institute something that is wrong, sinful, or evil.

Don’t get me wrong.  God did not want it to come to this.  If He did not allow for free will then He would not have had to place this law into effect.  If there was no free will, there wouldn’t be sin in the world.

God loves us so much that He allowed His perfect blameless son to undergo capitol punishment in order that we might be saved.