He could have summoned twelve legions of Angels to save Him.  He didn't.

Matthew 26:53-54 NIV

53 Do you think I cannot call on My Father,
and He will at once put at my disposal
more than twelve legions of angels?
54 But how then would the Scriptures be fulfilled
 that say it must happen in this way?

What was at stake was too important to deny:  Mankind's Redemption.