20 Then the mother of Zebedee’s sons came to Him with her sons, kneeling down and asking something from Him.
21 And He said to her, “What do you wish?” She said to Him, “Grant that these two sons of mine may sit, one on Your right hand and the other on the left, in Your kingdom.”
22 But Jesus answered and said, “You do not know what you ask. Are you able to drink the cup that I am about to drink, and be baptized with the baptism that I am baptized with?” They said to Him, “We are able.”
23 So He said to them, “You will indeed drink My cup, and be baptized with the baptism that I am baptized with; but to sit on My right hand and on My left is not Mine to give, but it is for those for whom it is prepared by My Father.”
24 And when the ten heard it, they were greatly displeased with the two brothers.
mother (v.20) — Mark 10:35 makes it clear that it was really James and John who were asking. They just used their mother, probably to gain sympathy.
sons (v.20) — James and John (Matthew 4:21)
grant (v.21) = lit. “command”
The disciples believed He was the Messiah who would reign. They had faith. But they didn’t understand that He would first have to suffer.
right hand (v.21) — The position next to His throne. They’d been told they would sit on twelve thrones (Matthew 19:28)
cup (v.22) — His suffering and death
The mention of baptism (vs.22-23) are not in the original manuscript of Matthew. They were copied from the parallel account in Mark 10:35-41.
you will indeed drink (v.23) — James was beheaded (Acts 12:2) and John was exiled to Patmos (Revelation 1:9)
it is for those (v.23) — these words were added by the translators. He wasn’t saying that He couldn’t give the positions, but that He could only give them to those for whom it was prepared.