Abu Dawud said: This hadith was also narrated by 'Abd al-Razzaq, from Ma'mar, from 'Amr ibn Muslim, from 'Ikrimah, from the Prophet ﷺ, as a mursal report (1).

2230 - Narrated to us al-Qa'nabi, from Malik, from Nafi', from Ibn 'Umar, who said: The waiting period ('iddah) of a woman divorced by khul' is one menstrual period (2).

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(1) Its narrators are trustworthy (thiqat).
It is found with 'Abd al-Razzaq in his Musannaf (11858), and from his chain it was also narrated by al-Daraqutni in his Sunan (3632) and (4027), al-Hakim in al-Mustadrak 2/206, and al-Bayhaqi in al-Kubra 7/455, as mursal.
It was also narrated by Ibn Abi Shaybah in his Musannaf 5/114 and 10/163-164, and Ahmad in al-'Ilal (5643) via the path of Abu al-Tufayl Sa'id ibn Hamd, from 'Ikrimah, as mursal.
It has preceded earlier in this work as connected (mawsul).

(2) Its chain is authentic (sahih), mawquf. However, the narrations of Sunan Abi Dawud differ regarding Ibn 'Umar's legal opinion. In the narration of Abu 'Ali al-Lu'lu'i: from Ibn 'Umar, who said: The waiting period of a woman divorced by khul' is one menstrual period. And in the narration of Ibn Dasa: The waiting period of a woman divorced by khul' is the waiting period of a divorced woman (al-mutallaqah).
This second narration is the one that agrees with what is in the Muwatta' according to the narration of Abu Mus'ab al-Zuhri (1614), and the narration of Yahya al-Laythi 2/565.
'Abdah ibn Sulayman narrated from 'Ubayd Allah ibn 'Umar, from Nafi', from Ibn 'Umar, who said: The waiting period of a woman divorced by khul' is one menstrual period — meaning, like the narration of Abu 'Ali al-Lu'lu'i. It was narrated by Ibn Abi Shaybah 5/114.
This indicates the authenticity of both narrations from Ibn 'Umar.
Accordingly, what Imam Ibn 'Abd al-Barr said in al-Tamhid 23/377, and Shaykh al-Islam Ibn Taymiyyah in Majmu' al-Fatawa 32/323 — that the most correct view from Ibn 'Umar is his legal opinion that the waiting period of a woman divorced by khul' is the waiting period of a divorced woman — is not accepted from them for two reasons:
First: 'Ubayd Allah ibn 'Umar narrated it from Nafi' as found with Ibn Abi Shaybah 5/114, and said in it: from Ibn 'Umar: The waiting period of a woman divorced by khul' is one menstrual period. This is a sound corroboration (mutaba'ah) of the narration of al-Lu'lu'i, from Abu Dawud, from al-Qa'nabi, from Malik. =