Pouring water from one container to another is an attribute of Temperance, a major arcana tarot card. Edit: And, of course, the Tarot depiction comes from the virtue itself. The card represents balance first and foremost, so Anakin being supposed to bring balance to the force immediately springs to mind.

I’m sure that if I wasn’t as tired as I am right now, I could come up with a plausible theory for him standing in the sea. Beach/sand connection maybe? I’ll leave that to someone else.

But I do believe you can eke out some sense out of this picture if you really try.