After they've set all the clocks forward in a shop to strike noon at the same time as a prank.
Molly: Now we wait.
Mr. Magorium: No. We Breathe. We Pulse. We Regenerate. Our hearts beat. Our minds create. Our souls ingest. Thirty-seven seconds, well used, is a lifetime.
When Mr. Magorium says goodbye to the Emporium one last time. Also counts as the movie's biggest Tear Jerker moment.
Right before that, he has his final conversation with Molly. He starts off by talking about himself with an analogy to Shakespeare. But at the end of it all, the last thing he says to her is this advice for her:
Mr. Magorium: Your life is an occasion. Rise to it.
When Molly is finally able to revive the Emprorium.
YMMV a bit on that one. While it was a wonderful scene, someone who has training in Symphonic music (like this troper) will probably be distracted by the fact that the music Molly is "conducting" doesn't match her movements at all. It's obvious that the director didn't try to line up Natalie Portman to the music or vise versa.