Looking to find the film this quote is from

The quote is 'Alas this is one adventure on which I cannot join you', and we thought it was from an Indiana Jones movie, but it seems it isn't. Anyone know?

Was this from one of the Harry Potter movies? Dumbledore saying it to Harry.

i think it was Harry Potter and the Philosopher's Stone

I'm thinking that sounds like something from LoTR movies, but I'm not finding any lines which are close.

It sounds like something that may have been said in The Mists of Avalon. Maybe by Merlin.

Sounds from the Hobbit or Lord of the rings

Gods this quote seems so familiar but I just can't place it. GRRRR!!!!

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Did you know that in the 1980s movie PREDATOR the titular character was not originally portrayed by Kevin Peter Hall. It was in fact Jean-Claude Van Damme donning a much more insect inspired full body suit before he left the production which then led to the recasting and redesigning of the famous hunter.

It does. I was thinking maybe Man of La Mancha, but probably not.

Alas, this is one question for which we cannot answer you...

I cannot identify the movie, but I would hazard to guess that its screenwriter was a fan of E. Phillips Oppenheim (https://en.wikipedia.org/wiki/E._Phillips_Oppenheim), as the latter's 1923 novel Michael's Evil Deeds contains the following:

"I deeply regret," Demayel announced, "that this is an adventure on which I cannot accompany you. If I were to show myself in the Quartier, I should not only endanger your lives but I should of an absolute certainty forfeit my own. Monsieur Santel here," he added, turning to his companion, "will take command of the expedition. Lund is in one of the cars outside. A sufficient force of gendarmes have already penetrated secretly into the Quartier. It remains only for me to wish you good fortune."

That particular novel was never turned into a movie, but I seem to recall very similar dialogue in some old (1940s?) adventure flick.