Al-Baghawi said:

“This is an authentic hadith.”

Musa ibn Dawud—who was truthful but prone to errors—and ‘Ali ibn ‘Ayyash—who was trustworthy and precise—also corroborated it, as recorded by Abu ‘Awanah.

Sa‘id ibn Sulayman—al-Dabbi al-Wasiti, a trustworthy hadith memorizer—also corroborated it, as recorded by al-Bayhaqi.

I say: All of them narrated the hadith with the wording: “a night.”

They were contradicted by ‘Ali ibn Nasr al-Jahdami, who narrated it to us from Layth ibn Sa‘d through the same chain, but said: “a day” in place of “a night.”

Muslim alone recorded it, adding at its end:

“Layth said: The non-Arabs among us take precautions against this in December.”

Al-Nawawi reconciled the two versions, “a night” and “a day,” saying:

“There is no contradiction between them, since neither of them negates the other.”

I say: This ought to have been the case, were it not that our tracing of the narrators from Layth ibn Sa‘d has shown the anomalous nature of the narration stating “a day.” Al-Jahdami alone narrated it, contradicting the five trustworthy narrators who related it with the first wording. Their agreement upon it demonstrates al-Jahdami’s error and the anomalous nature of his narration. An anomaly is established on less evidence than this, as is known to anyone experienced in this noble field of knowledge.

Similar to this anomaly is what occurred in the hadith of ‘Umar: that he had vowed, in the pre-Islamic period, to observe i‘tikaf