Sunan Ibn Majah
3044
Sahih+3

It was narrated from Ibn ‘Umar that the Messenger of Allah (ﷺ) said:“May Allah have mercy on those who shave (their heads).” They said: “And those who cut (their hair), O Messenger of Allah!” He said: “May Allah have mercy on those who shave (their heads).” They said: “And those who cut (their hair), O Messenger of Allah!” He said: “May Allah have mercy on those who shave (their heads).” They said: “And those who cut (their hair), O Messenger of Allah!” He said: “And those who cut (their hair).”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi