I say: In our copy of al-Aṣbahānī, it appears with the wording cited above. Al-Ṭabarānī’s wording, as quoted by al-Mundhirī, is:

“Whoever has in his heart a mustard-seed’s measure of arrogance.”

Al-Haythamī likewise cited it (1/99) and also graded its chain of transmission good.

The hadith is authentic and has many supporting narrations, some of which are found in Ṣaḥīḥ Muslim on the authority of Ibn Masʿūd. I have chosen to mention this version because of the account of ʿAbd Allāh ibn Salām—may Allah be pleased with him. *

From the Upbringing of Our Prophet and the Character of Our Righteous Predecessors

3258—(“Yes; do not answer him in kind. Rather, say: ‘May Allah forgive you, O Abū Bakr! May Allah forgive you, O Abū Bakr!’”)

Aḥmad (4/58–59) and al-Ṭabarānī in al-Muʿjam al-Kabīr (5774) narrated it through several routes from Mubārak ibn Fuḍālah: Abū ʿImrān al-Jawnī narrated to us from Rabīʿah al-Aslamī, who said:

I used to serve the Messenger of Allah, peace and blessings be upon him. He granted me a piece of land, and he granted Abū Bakr a piece of land. Then worldly prosperity came to us, and we disagreed over a branch of a date palm. Abū Bakr said, “It is within the boundary of my land!” while I said, “It is within my boundary!” Some words passed between Abū Bakr and me, and Abū Bakr said something to me which I disliked. He regretted it and said to me, “O Rabīʿah, say the same to me, so that it may be requital.”

I said, “I will not do so.” Abū Bakr said, “You must say it, or I shall seek the Messenger of Allah’s judgment against you.” I replied, “I will not do so.” He then relinquished the land.

Abū Bakr—may Allah be pleased with him—went to the Prophet, peace and blessings be upon him, and I followed behind him. Some men from Aslam came to me and said, “May Allah have mercy on Abū Bakr! Over what matter is he seeking the Messenger’s judgment against you, when he was the one who said what he said to you?!” I said, “Do you know who this is? This is Abū Bakr al-Ṣiddīq,”