What does Mark 10:35 mean?

Mark first mentions James and John after Jesus' temptation, when He calls them to follow Him. James and John do so, leaving behind their father, Zebedee, and their fishing business (Mark 1:19–20). With Peter, they become the inner core of Jesus' disciples. Only these three watch Jesus raise a little girl from the dead (Mark 5:35–43) and see the transfiguration (Mark 9:2–13). James and John's mother is one of the few who stay near Jesus during the crucifixion (Matthew 27:55–56). It's easy to mock James and John for their request, especially as it comes on the heels of Jesus' third prophecy of His death. It's important to remember three things, however. First, we don't know how long after Jesus' prophecy James and John make their request. Second, other Scripture makes it clear that these men don't fully understand Jesus will die (Luke 18:34). Third, their mother apparently either pushes them to ask or makes the request on their behalf (Matthew 20:20–21).

In addition, although James and John have heard Jesus prophesy His death three times, they have seen Him glorified, speaking with Moses and Elijah, and heard Him honored by God (Mark 9:2–8). And Jesus consistently refers to Himself as the "son of man" whom Daniel describes as a ruler given dominion over the world (Daniel 7:13–14).

We aren't told how many people are with Jesus and the Twelve at this point (Mark 10:32). James and John's mother is part of a group of women who followed Jesus from Galilee (Matthew 27:55–56), and sometime before, Jesus had sent out seventy-two disciples to perform miracles (Luke 10:1–12). Shortly, Jesus will enter Jerusalem to a crowd who greets Him like the Messiah (Mark 11:1–10), so it's reasonable to think Jesus and the disciples are followed by a mob that means to make Jesus king (John 6:15). James and John see the signs that Jesus' kingdom is imminent, and they want to make sure their seats are reserved.