Sunan an-Nasai 19802
In-book no 5066أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا بِشْرٌ، عَنْ يُونُسَ، عَنِ الْحَسَنِ، وَمُحَمَّدٍ، قَالاَ التَّرَجُّلُ غِبٌّ .
It was narrated that Al-Hasan and Muhammad said: "Combing one's hair (should be done) every other day."