[14] Now at that time the group-of-six bhikkhus smoothed their hair with a brush; they smoothed their hair with a comb; they smoothed their hair with the fingers of the hand used as a comb; they smoothed their hair with beeswax mixed with oil; they smoothed their hair with oil mixed with water. People criticized, complained, and spread it about, … "just like householders who enjoy sensual pleasures" … They reported this matter to the Blessed One. …
"Bhikkhus, the hair is not to be smoothed with a brush; the hair is not to be smoothed with a comb; the hair is not to be smoothed with the fingers of the hand used as a comb; the hair is not to be smoothed with beeswax mixed with oil; the hair is not to be smoothed with oil mixed with water. Whoever should smooth it thus commits an offense of wrong-doing (dukkaṭa)."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.