God's justice, eh? So "Do unto others as you would have them do unto you" and Love thy neighbor" and all that, but don't hold God to the same standard, huh? Jesus is our example, and, by extension, God, yet we shouldn't act like him?
I'm sure you'll agree with this - how about you believe in the god you want, and I'll disbelieve in the god I want - a god that would seem to adhere to a double standard if he actually existed.
What double standard? "Do unto others as you would have them do unto you."
Let's walk through the sequence of events.
God cloaks himself in mortal flesh (we are talking the Christian triune God here) and lives life from birth to adulthood, which is good so far. Carpentry is creative work, he's in the right business.

But he feels called to become a Rabbi, a man of religion. (Whoa, who would have seen that one coming?) Now, to set the example for how people are to treat one another, a difficult to match example I confess, He (in his human manifestation) gives it all up in the prime of his life for everyone else's benifit.
That's the theme.
The hard part to explain, or illustrate, is how the part in mortal flesh is sufficiently decoupled from "all that is God" to make the human experience genuine. I am not good making an anology or mechanism for that. Some day I might come up with one, sorry. (EDIT< see below "DR")
If the human experience (Jeshuah Ben Joseph) isn't in some way decoupled temporarily from the entirety of God, then you can certainly call the Sacrifice a bit of a show, since He knows he just sloughing off (at the God level) the mortal coil like the skin off of a snake.
Anyway, given that theme, who can give anymore than that? That's doing unto, and for others, with everything you've got (in the human aspect).
What double standard?
DR
EDIT: Here's a very coarse analogue, based on a transition. A woman goes through a lot of pain and anguish to give the gift of life during child birth. Her sacrifice, or her temporary painful and bloody phase, passes, something new and good comes of it, and she returns pretty much to her pre "man that hurts" condition afterwards. A very, very coarse analogy to be sure, for all that the theme does involve the giving of life, pain, and sacrifice in the process.