Before Matt 20:17–28, Jesus had just taught twice that many who are last shall be first, and many who are first shall be last (Matt 19:30; 20:16). Just off the heels of this lesson, Jesus announced His death for a third time in Matthew (Matt 20:17–20; cf. 16:21–22; 17:22–23), and the disciples showed they failed to learn this lesson. Though they had been promised special positions in the kingdom when Jesus comes again (Matt 19:28), James and John asked Jesus to give them positions of prominence in the kingdom—to sit at his right and left hands (Matt 20:21–22). Jesus corrected their thinking, and the ten were indignant with them, most likely because they, too, desired such positions (Matt 20:23–24). They simply didn’t think quick enough to be first in asking Jesus for such status.
Jesus then went on to teach a powerful lesson mentioned above: in order to be great, we should all serve as slaves, just like Jesus.
Notice how Jesus stresses this lesson in Matt 20:25–28. First, he makes it clear in Matt 20:25–26a that the disciples were not to lord it over one another as did the pagan rulers. Second, Jesus explicitly commanded them to serve as slaves, just as he was doing. What helps to stress this command is the parallelism found in Matt 20:26b–27. Jesus moves from general to specific terms in order to emphasis his point. Notice:
But whoever would be great among you // must be your servant (Matt 20:26b)
And whoever would be first among you // must be your slave (Matt 20:27)
We all battle the remnants of sin in wanting to be first before others, our peers, and anyone who cares to notice. Jesus tells us this: if you desire to be great and first among others, first be their servant, and even their slave.
And what does this look like? It looks like Jesus whose purpose in life was to give himself as a ransom for the many he would save (Matt 20:28). And in doing so, he was exalted to the right hand of the Father in glory. He lived as last and is now exalted above all mankind (cf. Phil 2:5-11).
A question we should ask ourselves is this: why do we serve Jesus? Is it for accolades now? Perhaps we are so spiritual as to realize that reward comes later. But, even then, do we have a self-serving desire to have a better seat than others in the kingdom to come? We should desire reward, but not for our own sake.
If we desire to be first, we should desire to be first in the eyes of God. And to be truly first in His eyes, we should make ourselves last and be a slave to others, just like Jesus.