en_tn/act/21/22.md

The Jerusalem elders continue to speak to Paul.

What should we do?

The word "we" refers to the elders. (See: rc://en/ta/man/translate/figs-exclusive)

four men who made a vow

This was the kind of vow where the person would not drink alcohol or cut their hair until the end of the set period of time. Alternate translation: "four men who made a promise to God".

pay their expenses for them

The expenses would go towards buying a male and female lamb, a ram, and grain and drink offerings. Alternate translation: "pay for what they will need."

keep the law

"live a life that conforms to the Law of Moses and other Jewish customs"