(70) باب الْفَرْقِ
Narrated Ibn `Abbas:
The Prophet (ﷺ) used to copy the people of the Scriptures in matters in which there was no order from Allah. The people of the Scripture used to let their hair hang down while the pagans used to part their hair. So the Prophet (ﷺ) let his hair hang down first, but later on he parted it.
Reference: Sahih al-Bukhari 5917
In-book reference: Book 77, Hadith 132
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 72, Hadith 799