故舊之情 For the Sake of Old Acquaintance
你才欺我愛妾，打上我門何也？」大聖笑道：「我因拜謁長兄不見，向那女子拜問，不知就是二嫂嫂。因他罵了我幾句，是小弟一時粗鹵，驚了嫂嫂。望長兄寬恕寬恕。」牛王道：「既如此說，我看故舊之情，饒你去罷。」你才欺我爱妾，打上我门何也？」大圣笑道：「我因拜谒长兄不见，向那女子拜问，不知就是二嫂嫂。因他骂了我几句，是小弟一时粗卤，惊了嫂嫂。望长兄宽恕宽恕。」牛王道：「既如此说，我看故旧之情，饶你去罢。」
逐句解 Line by line
"but just now you insulted my beloved concubine and came beating at my gate. What of that?"
才 marks the second charge as immediate, where the first was five years old. 打上我門 is to force your way to another man's door: an offence against the household rather than against a person.
The Great Sage laughed and said, "It was because I came to wait upon my elder brother and did not find him that I made my enquiry of that woman, not knowing that she was my second sister-in-law."
拜謁 is to call formally upon a superior. 二嫂嫂 — second sister-in-law — grants the Jade-Faced Princess the standing of a wife, which is precisely the concession the Bull King wants and precisely what the Rākṣasī would refuse to make.
"Because she railed at me a few words, your younger brother was for the moment coarse and rough, and startled my sister-in-law. I beg my elder brother to forgive it, to forgive it."
粗鹵 is coarse and blunt: he is pleading temperament, not malice. And the doubling of 寬恕 is the vernacular intensifier — forgive it, forgive it — matching the 周濟周濟 of the next passage.
The Bull King said, "Since you put it so, I will have regard to our old acquaintance and let you off. Go."
罷 is the imperative ba, not the verb bà; the sealed corpus treats the parallel 出來罷 the same way. 故舊之情 is the claim of long acquaintance — the very thing the Great Sage came armed with and has not yet had to name.
The apology is a small masterpiece of misdirection. He explains that he questioned the woman only because he could not find her husband, which is true; that he did not know who she was, which is true; and that he was rough with her because she abused him first, which is also true. What he leaves out is that he drew a weapon, called her a bought wife, and chased her home. The account is accurate and thoroughly dishonest.
The concession that does the real work is 二嫂嫂, second sister-in-law. By using it he recognises the Jade-Faced Princess as a wife of the house, which flatters the Bull King exactly where he is most exposed and costs the Great Sage nothing. It is also, from the Rākṣasī's point of view, a betrayal — and he will be back at her door before the chapter is out.
The pardon is granted on the ground of 故舊之情, old acquaintance: the sworn brotherhood he has been trading on for two chapters without ever having to state it. He gets the benefit of it here without asking, which is the best possible position to be in, and he is about to throw it away by asking for something else.