The Apostle Paul writes that you offer your bodies a sacrifice to God because of His mercies to you. Jesus taught the same. In the final days of His earthly life, Jesus prepares His disciples for the great difficulties they will be facing. The crucial element of their service to Him requires their absolute submission to Him without any reservations. His own crucifixion demands this. King Jesus dies for them. How can they do less for Him- In the same way we too must die to self in order to serve our Eternal King.