A man amongst us begot a boy whom he named Al-Qasim. On that the Ansar said, (to the man), "We
will never call you Abu-al-Qasim and will never please you with this blessed title." So, he went to the
Prophet and said, "O Allah's Messenger (ﷺ)! I have begotten a boy whom I named Al-Qasim and the Ansar
said, 'We will never call you Abu-al-Qasim, nor will we please you with this title.' " The Prophet (ﷺ) said,
"The Ansar have done well. Name by my name, but do not name by my Kunya, for I am Qasim."
Sahih al-Bukhari Book 57, Hadith 24