How can the Son not know what the Father knows? Matthew 24:36    (NLT)
  Mark 13:32 (NLT) 
  
  36 “However, no one knows the day or hour when these things will happen, not even the angels in heaven or the Son himself. Only the Father knows.”


Now hold on a minute here... in according to the doctrine of the Trinity, God the Father and God the Son are the same God, yet the Father knows something the Son doesn't? What's going on here?
The theological term here is kenosis

From Phillipians 2:6-7


  though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself ...


In short, Jesus gave up the perks of being God in order to identify with humanity.