佛說目連問戒律中五百輕重事經 1.128

1.128

問：「受戒為有時節不？」答：「唯後夜不得。初夜中夜無燈燭亦不得，要須相覩形色乃得。」

Question: "Is there a proper time for receiving the precepts?"
Answer: "Only [during] the last watch of the night is it not permitted. During the first watch and middle watch, if there are no lamps and candles, it is also not permitted; they must be able to see each other's forms and colors for it to be valid."