是我師慈悲 The Children Are Already Safe
行者笑道：「實不相瞞，籠中小兒，是我師慈悲，著我藏了。你且休題甚麼資財相謝，待我捉了妖怪，是我的功行。」行者笑道：「实不相瞒，笼中小儿，是我师慈悲，着我藏了。你且休题甚么资财相谢，待我捉了妖怪，是我的功行。」
逐句解 Line by line
Pilgrim said with a laugh, "To tell you the plain truth, the children in the coops were hidden away by me, at my master's compassionate bidding.
著我藏了 takes zhuó, the dispatching reading — his master set him to hide them. It is the same sense the king's own two orders took earlier in the chapter, and the third time the character does that job here. The credit goes to Tripitaka, and the novel is careful about that: the idea was his, the labour was Wukong's.
You may leave off talking about repaying me with goods and money. Once I have caught the demon, that is my own meritorious work."
功行, merit-and-practice, is the Buddhist and Daoist accounting term for what a practitioner accumulates by doing good — a spiritual ledger rather than a wage. Wukong is not refusing payment out of modesty. He is saying the deed is already worth something to him, and money would only take that away.
The single most important fact in the kingdom — that the children are alive — has been sitting in Wukong's pocket for a whole chapter while everybody thanked him for other things. He mentions it now, in passing, while declining a fee.
His reason for refusing is worth sitting with. Merit in this system is earned by the act and cancelled by the reward; a paid rescue is a transaction and scores nothing. It is the one moment in the chapter where Wukong sounds like a monk rather than a bruiser.