Abu Dawud said: Ja'far ibn Sulayman narrated it from Abu 'Imran, from Anas, who said: He did not mention the Prophet, peace and blessings be upon him. He said: A time was set for us, and this is more correct.¹

4201 — Ibn Nufayl narrated to us, Zuhayr narrated to us: I read to 'Abd al-Malik ibn Abi Sulayman, and 'Abd al-Malik read it to Abu al-Zubayr.
And Abu al-Zubayr narrated it from Jabir, who said: We used to leave the whiskers untrimmed except during Hajj or 'Umrah.²

Abu Dawud said: Al-istihdad is shaving the pubic region.

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¹ The phrase "and this is more correct" is an addition we have confirmed from manuscript (H), and it is in the narration of Ibn Dasa. In the narration of Ibn al-'Abd — as indicated in manuscript (A) — it reads: "Sadaqah is not strong." This carries the same meaning as what is found with Ibn Dasa, because it entails affirming the correctness of the narration of Ja'far ibn Sulayman, which is not explicit in raising [the report to the Prophet], over the narration of Sadaqah, which is explicit in raising it.

² Its chain of transmission is weak, and its text contains inconsistency. Abu al-Zubayr — who is Muhammad ibn Muslim ibn Tadrus al-Makki — is a mudallis who used ambiguous wording in transmission. Ibn Nufayl: he is 'Abdullah ibn Muhammad ibn 'Ali ibn Nufayl al-Harrani, Abu Ja'far.
It was also recorded by al-Ramhurmuzi in "Al-Muhaddith al-Fasil," p. 433, and by Ibn 'Adi in "Al-Kamil," 5/1940, via the path of Abu Ja'far al-Nufayli, with this chain.
It was also recorded by al-Khatib al-Baghdadi in "Al-Kifayah," p. 265, from Ahmad ibn 'Abd al-Malik al-Harrani, from Zuhayr ibn Mu'awiyah, with it, but with the wording: "We would not leave the whiskers untrimmed except during Hajj or 'Umrah," thus reversing the meaning.
It was also recorded by Ibn Abi Shaybah 8/567 and al-Bayhaqi 5/33 via the path of Ash'ath ibn Sawwar, from Abu al-Zubayr, from Jabir. Its wording with Ibn Abi Shaybah is: "We were commanded to let the whiskers grow fully and trim the mustaches," and its wording with al-Bayhaqi is: "We were commanded to let the whiskers grow fully during Hajj and 'Umrah."
It was also recorded by al-Tabarani in "Al-Awsat" (8908) via the path of 'Abdullah ibn Lahi'ah, from Abu al-Zubayr, from Jabir: that the Prophet, peace and blessings be upon him, forbade cutting the whiskers. Ibn Lahi'ah had a poor memory.
Al-Sibal: with a kasrah on the first letter and a lightened second letter, plural of sabalah, which is the long part of the beard hair.