The Prophet ﷺ saw a boy whose head had been partly shaved while the rest of the hair was left untouched. He forbade them from doing this and said, "Shave all of it or leave all of it."
حدثنا أحمد بن حنبل حدثنا عبد الرزاق حدثنا معمر عن أيوب عن نافع
أن النبي ﷺ رأى صبيا قد حلق بعض شعره وترك بعضه فنهاهم عن ذلك وقال احلقوه كله أو اتركوه كله
[Sahih] Nasai narrated it in Zinah, chapter on the permission to shave the head, hadith: 5051, from the hadith of Abdul-Razzaq, with this wording. It is also found in Musannaf Abdul-Razzaq, hadith: 19564, and Musnad Ahmad: 2/88. Muslim also narrated it, hadith: 2120, from the hadith of Abdul-Razzaq, with this chain, in abridged form, and he did not give the full wording.