專為客來 It Is About The Guests
如今又有客在外面，有話且慢慢說罷。」眾怪道：「告稟師兄：這樁事，專為客來，方敢告訴；若客去了，縱說也沒用了。」如今又有客在外面，有话且慢慢说罢。」众怪道：「告禀师兄：这桩事，专为客来，方敢告诉；若客去了，纵说也没用了。」
逐句解 Line by line
"And now there are guests outside as well. If you have something to say, let it keep and we shall talk at leisure."
且 here means "for now", and 慢慢說 — talk slowly — is the standing polite way of saying later. He is doing what any host does when family corners him mid-party. The whole line is a door being gently closed.
"We beg to report, elder brother," said the monsters. "This business is entirely on account of the guests' arrival; only now do we dare tell it;"
告稟 is formal, the verb for reporting upward to a superior, and it sits oddly in the mouths of women who a moment ago were calling him brother — they have switched register to get his attention. 專為 takes 為 as wèi, on account of, for the sake of. And 樁 is the measure word for an affair or a piece of business, the way English says "a matter".
"If the guests go, then telling you will be no use at all."
縱 means even if, granting that — a concessive that survives in 縱然 today. The sentence closes their argument in ten characters: the news is not about the guests, the news IS the guests, and it has a deadline.
This is a scene about a man who will not listen, and the women's counter is very well made. He has just told them the classic host's line — later, not now, not in front of company. Their answer is that later does not exist: the thing they came to say is only worth saying while the company is still in the building.
It is also, structurally, a piece of tension engineering. The reader already knows what the women are going to say. The whole passage exists so that they cannot say it yet — because a Daoist who wants to get back to his guests keeps interrupting. Every line of delay here is a line the pilgrims spend sightseeing in a courtyard.
And there is a quiet joke in the politeness. He is refusing to discuss family business in front of guests. The family business is the guests.