The Potter's Cup

Jesus said to them. “Can you drink the cup I am going to drink?”
“We can,” they answered.

Matthew 20:22

On the heels of outlining the principle of being least, the disciples are suddenly appearing to jockey for position.  Since He just finished detailing the matter in which He would be killed and then rise from the dead, He responds to them by asking them this question: "Can you drink from the cup that I'm going to drink?"  In other words, can you go through what I'm going to go through?  Their answer is founded in a stew of cockiness and ignorance.  But in a stroke of prophecy, He declares they will indeed end up drinking from that cup.

But lest they lose sight of a foundational principle that He wants to make clear, He takes advantage of the sudden strife in the immediate family, loses the pedagogy of speaking in parables and becomes blunt in stating plainly: If you're yearning to be great, you must become a servant.  Hence, the cup from which they will be drinking.  This is the way of Jesus.  This is the mandate and economy of the Kingdom of Heaven.

Is it really all about greatness, though?  Sitting at Jesus' right or left is not an issue for Him to decide; the Father will be doing that.  And the disciples would possibly have been quite surprised and possibly indignant (from their current understanding) if they knew then who that going to be:

And God raised us up with Christ and seated us with him in the heavenly realms in Christ Jesus, in order that in the coming ages he might show the incomparable riches of his grace, expressed in his kindness to us in Christ Jesus.

Ephesian 2:6,7

This falls squarely in line with the parable of the workers in the vineyard (20:1-16).

Let us, then, serve not for the sake of earning greatness.  But rather, let us serve in the noble and great heart of our Servant King.