What does Matthew 20:21 mean?

The "mother of the sons of Zebedee," James' and John's parent, has approached Jesus with great respect (Matthew 20:20). She has kneeled before Him in humility to make this specific request. Some scholars speculate that this woman may have been Salome (Matthew 27:56; John 19:25), possibly Jesus' aunt—His mother Mary's sister—and that James and John were his cousins. That may be why she felt bold enough to ask such a thing.

What she asks is huge: She wants Jesus to commit, right now, to declaring James and John will sit at Jesus' right and left hand in His kingdom. In this era, the closer someone was seated to the king, the more power that person had in the kingdom. James and John, through their mother, are asking Jesus to make them the most powerful men in His kingdom, second only to Jesus Himself.

It is an understatement to call this a bold request. It would be an audacious thing to ask even if Jesus had, in fact, come to overthrow the Romans and return Israel to power and glory amongst the nations. This was what many people in that era expected the Messiah to do.

Jesus had not come to do any such thing at this time, however. He had come to plant the seeds of the kingdom of heaven, the eternal kingdom over which He will reign forever. That makes this request of Him even more enormous. If Jesus said yes, He would be declaring James and John as second only to Him for all eternity. Jesus will show patience and understanding in denying this request they do not understand.