Because he emptied himself of that power and authority by becoming a man.
He needed it all back for his ministry.
What does that verse say that he emptied himself of?
Maybe the context tells us?
Philippians 2
If there be therefore any
consolation in Christ, if any comfort of love, if any fellowship of the Spirit, if any bowels and mercies,
2 Fulfil ye my joy, that ye
be likeminded, having the same love, being of one accord, of one mind.
3 Let nothing be done through strife or vainglory; but
in lowliness of mind let each esteem other better than themselves.
4 Look not every man on his own things, but every man also on the things of others.
5
Let this mind be in you, which was also in Christ Jesus:
6 Who, being in the form of God,
thought it not robbery to be equal with God:
7 But made himself of no reputation, and
took upon him the form of a servant, and was made in the likeness of men:
8
And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross.
9 Wherefore God also hath highly exalted him, and given him a name which is above every name:
One theme running through the context is what we, including Jesus Christ think
Did Jesus puff himself up? Should we?
Did Jesus come to be ministered to or to minister? Should we come to be ministered to or to minister?
Did Jesus exalt himself being full of pride or humble himself?
Should we exalt ourselves being full of pride or humble ourselves?
Did Jesus Christ choose to lord it over people or to serve?
Should we choose to lord it over people or to serve?