“Judge not” means do not try to decide who goes to heaven or hell. Only God has enough information - and grace - for that.
I am reminded of when I worked at a prison hospital, and a convicted murderer was dying......now flash to the scene in hospitals when non criminals are dying, and recall the peace that seems to fall over them just before they die.............now back to this convict....whom I witnessed having abject fear in his eyes, shortly before he died....it made me think he had a glimpse of where he was headed!!
True.
But the rest of us can certainly say this world will be a better place without him.
I think it's safe to assume that an unrepentant murderer will not step foot in Heaven...God gives a whole list of those who won't be in Heaven. John 7:1 means not to be a hypocrite. If I see a murderer, I can safely say he is going to go to Hell if he doesn't repent and accept Jesus. The Bible doesn't tell us we can't judge, it gives us the conditions that we are to use.
That said, the only way any of us are saved is by the grace of God after we accept his Son, Jesus,as Lord and repent of our sins. I wish everyone would do that, but unfortunately most people won't.
But my judging does not affect the outcome.
They are going where God determines, not me, so even if I judge them, it's my opinion.
However, God also gives us commands TO judge with righteous judgment.
And He gives us standards by which to do that.
Unrepentant murderers will go to hell and I will not weep for them.
They were shown far more mercy in this life than they showed their victims and they deserve.
God instituted capital punishment and it should be used in cases as clear cut as that.
As I’ve gotten older, I’ve even ceased hoping someone like this suffers on the way out. Dead is dead. If God decides to mete out punishment, they’ll know suffering well beyond the physical pain we may smugly wish on them for a few days/weeks/hours.