What does Matthew 20:20 mean?

Mark's account of this moment (Mark 10:35–45) does not mention the mother of James and John. Mark simply left out the fact that their mother initiated this conversation, likely because he considered it their request, and their mistake, more than Matthew might have done. In truth, the main misunderstanding here is between Jesus and these two brothers. Supporting this possibility is that, in both passages, Jesus holds the sons responsible for the request, not their mother.

Matthew introduced James and John as the sons of Zebedee the fisherman in Matthew 4:21–22. Jesus later gave the pair the name "Boanerges," which means "sons of thunder." Perhaps this was because of their father's explosive personality or, more likely, it was because of their own (Luke 9:54).

According to many Bible scholars, the mother of the sons of Zebedee is likely a woman named Salome who is also the sister of Jesus' mother Mary. They build the case for this, in part, from all of the times Jesus' mother Mary is shown to be accompanied by her sister or a woman named Salome (Matthew 27:56; Mark 15:40; 16:1; John 19:25).

If their mother was truly Mary's sister, that would have made James and John first cousins to Jesus, in earthly terms. Perhaps that gives a hint as to why their mother would imagine it appropriate on some level to ask Jesus what she does in the following verse. Still, her request and their willingness to go along with it shows that all three of them misunderstood Jesus' mission on earth and their part in it.