Why was it allowed if it would result in his separation from God?
Ask God,
it is HIS PLAN for our SALVATION.
HIS PLAN is PERFECT, eternally forever past and present and future,
with no fault, with not even a spot or a wrinkle or any darkness at all - no mistakes in HIS PLAN at all.
Think about this - all mankind was separated from GOD by sin.
No way to get to GOD.
GOD always knew this - even before HE created the world GOD KNEW THIS.
GOD PLANNED A WAY - JESUS birth as a man (in the midst of a wicked evil generation) , HIS crucifixion/ sacrifice/ shedding HIS BLOOD to atone for the sins of mankind, and HIS RESURRECTION!
HALLELUYAH ! RESURRECTION LIFE !!!!
Always PLANNED, all along, for all who are in CHRIST JESUS.
We who were enemies of GOD, all our lives, HE DIED FOR, to
REDEEM US WITH HIS BLOOD.
HE bore our sins and our illness upon HIMSELF.
So we could be no longer separated from GOD,
but
so great is YHWH'S LOVE for us - HE made a WAY for us to be becoming HIS OWN CHILDREN. (in JESUS! ) ...
JESUS suffered separation/ punishment/ beatings till no flesh was left on HIS back (ONE stripe), stoning that tore HIS flesh,
and crucifixion
FOR US.
FOR OUR SINS.
And HALLELUYAH ! DEATH could NOT HOLD HIM!
HE IS ALIVE FOREVER, never to die again, ever.
So we can have the same hope for resurrection with HIM.