The third reading follows on from the second, and tells of the spreading of palm branches as Jesus entered (John 12:12-19). It is the parallel account to the Matthew passage for day 1.
It is easy to focus on verse 16 and think his disciples were pretty dumb 'These things His disciples did not understand at the first; but when Jesus was glorified, then they remembered that these things were written of Him, and that they had done these things to Him'. They seemed not to put the prophesies and the crowd's reactions together.
Hindsight is always 20-20 vision, and although maybe they should have got it, they didn't, and we need to be careful to judge too quickly. That said, even among a people we moderns might sometimes patronise as being unsophisticated, people didn't rise from the dead everyday, and Lazarus was proof before their eyes Jesus was doing something radical. But while the disciples didn't understand it fully, the Pharisees were challenged by it, and sought to put both Jesus and Lazarus to death.
So let's not think that we have Jesus fully worked out, and going back to Scripture again and again to make sense of his life and mission is an imperative to all who would call themselves followers, and the place to start for those who want to make sense of him, coming as it were from the outside of this understanding.
And in all of this, if it took Jesus' glorification for the disciples to finally piece it together, it might take Jesus' return for us to make full sense of everything. For now, we are to step forward in faith without arrogance, hope without thinking we can be so certain that we have nothing to learn or can never be surprised.