To shave the head and to have the head-hair cut short on finishing the Ihram

Narrated `Abdullah bin `Umar: Allah's Messenger (ﷺ) said, "O Allah! Be merciful to those who have their head shaved." The people said, "O Allah's Messenger (ﷺ)! And (invoke Allah for) those who get their hair cut short." The Prophet (ﷺ) said, "O Allah! Be merciful to those who have their head shaved." The people said, "O Allah's Messenger (ﷺ)! And those who get their hair cut short." The Prophet (ﷺ) said (the third time), "And to those who get their hair cut short." Nafi` said that the Prophet (ﷺ) had said once or twice, "O Allah! Be merciful to those who get their head shaved," and on the fourth time he added, "And to those who have their hair cut short."