What does Mark 11:19 mean?

Those mentioned in this verse aren't the chief priests and scribes of Mark 11:18, but Jesus and the disciples. During the time between the triumphal entry and the Passover, they stay on the Mount of Olives during the evening and return to Jerusalem each day (Luke 21:37–38). Bethany sits on the southeastern slope of the Mount of Olives, a two-mile or three-kilometer walk to the Temple Mount. The text doesn't say that they see Mary, Martha and Lazarus every evening, but it's likely. The group does eat with them at least the night they first arrive in Bethany (John 12:1–2).

Soon, Jesus and the disciples will eat dinner in Jerusalem and then go to the Mount of Olives, to the garden of Gethsemane, where Jesus will be arrested (Mark 14:13–14, 32). Until then, it seems Jesus spends evenings with close friends including a group of women from Galilee who see to His more practical needs (Matthew 27:55).

Out of all these people, it may be that only Mary of Bethany even remotely understands what is going on. She anoints Jesus with perfumed ointment, preparing Jesus' body for burial (Mark 14:3–8). Mary has paid very close attention to Jesus' teaching (Luke 10:38–42). As a woman, she has little hope of a prominent place in any kind of earthly kingdom, so it may be her understanding is not clouded by personal gain as the disciples' is (Mark 10:35–37). Jesus is God and doesn't need human support, but He is also a man with emotional distresses, through which His friends can encourage Him (Mark 14:34). As He faces an increasingly antagonistic group of religious leaders and a death on a cross, He consistently returns to the company of His friends and, possibly, the only one who understands what He will face.