Most of this chapter forms a chiastic structure:
1a) Mat 20:1-16, The parable of the workers in the vineyard;
central axis) Mat 2o:17-19, Jesus predicts His death and resurrection;
2a) Mat 20:20-28, The greatest in the kingdom is the servant of all.
At first I couldn’t see how the parable of the workers in the vineyard would pair with the mother of James and John asking for thrones for her sons. I was working all kinds of different combinations instead, but nothing fell out. But here is the common theme between the two:
In the parable of the workers in the vineyard, the laborers who were hired first thought they would receive greater compensation than the other workers. But no, those who were hired last received their compensation first, and it was equal to the compensation of everyone else. Jesus told His disciples, The last will be first, and the first last (vs. 16).
The mother’s request for her sons, was for greater authority or recognition than the other disciples. She had essentially the same expectation, or was hoping for the same outcome, that the first laborers in the vineyard had. But no, those who wished to be great, must instead serve. Jesus told His disciples, Whoever desires to be first among you, let him be the last (the slave, vs. 27).
I sometimes wonder if the one who desires greatness, recognition, and advancement, who covets or craves to be above others, can truly serve as slaves of all. First, it seems to me, God works with that person to excise that desire from them, so that they can be truly like Jesus, who is gentle and lowly in heart, not coveting recognition and proclamation and the praise of men.