When will the priest be finished?

Hint 1 of 8:

It does seem like he takes forever to polish the chalice.

Hint 2 of 8:

It is obvious you need to do something to trigger its return.

Hint 3 of 8:

Right and left click on all of the tombs.

Hint 4 of 8:

Find a way to examine the stained glass window more closely.

Hint 5 of 8:

Simply using the lens on the window directly will accomplish nothing.

Hint 6 of 8:

Look at the statue carefully.

Hint 7 of 8:

Did you notice you can use part of the statue?

Hint 8 of 8:

Use the lens on the scroll in the knight's hand.