Ati reported, I came with Ibn Umar from Arafat to Muzdalifa, and he did not cease saying takbir and tahlil until we reached Muzdalifa. He gave the call to prayer and the iqamah, or he ordered a man to give the call to prayer and the iqamah, and he led us in the Maghrib prayer of three rakahs. Then he turned to us and said, "The prayer." So he led us in the Isha prayer of two rakahs, then he called for his supper.
أقبلت مع ابن عمر من عرفات إلى المزدلفة فلم يكن يفتر من التكبير والتهليل حتى أتينا المزدلفة، فأذن وأقام أو أمر إنسانا فأذن وأقام فصلى بنا المغرب ثلاث ركعات، ثم التفت إلينا فقال: الصلاة فصلى بنا العشاء ركعتين، ثم دعا بعشائه.
Abu Dawud (1933) narrated it from Musaddad, who said, Abu Ahwas narrated to us, Ashath bin Salim narrated to us, and he mentioned it. He (that is, Ashath) said, Ilaj bin Amr informed me with a hadith similar to my father's hadith, from Ibn Umar, who said, Ibn Umar was asked about that, and he said, "I prayed with the Messenger of Allah ﷺ."Its chain of transmission is sahih, and its narrators are reliable except for Ilaj bin Amr, who is unknown. Ibn Hibban mentioned him in Thiqat, and two narrators reported from him, so he is "acceptable" according to the terminology of Ibn Hajar, and this is indeed the case, since he was corroborated. All these narrations from Ibn Umar are sahih, so we must either interpret them or judge some of them to be anomalous.Hafiz bin Qayyim, may Allah have mercy on him, held that there is inconsistency in the hadiths of Ibn Umar, and he said,"The correct view in all this is to adopt the hadith of Jabir, which is that the two prayers were combined with one call to prayer and two calls to start the prayer, for two reasons. The first is that the other hadiths besides it are inconsistent and conflicting. This hadith of Ibn Umar is extremely inconsistent, as already mentioned. It has been reported that Ibn Umar's practice was to combine the two prayers without any call to prayer or call to start the prayer. It has also been reported from him that he combined them with a single call to start the prayer, and that he combined them with a single call to prayer and a single call to start the prayer. It has been reported from him, traced back to the Prophet ﷺ, that the two prayers were combined with a single call to start the prayer. It has been reported from him, as a raised report, that they were combined with two calls to start the prayer, and also from him, as a raised report, that they were combined with a single call to prayer and a single call to start the prayer for both of them, and from him, as a raised report, that they were combined without any mention of a call to prayer or a call to start the prayer. All these narrations from him are sahih, so relying on them falls away, because of their conflict and inconsistency.The second reason is that it has been established as sahih, from the hadith of Jabir concerning the Prophet's ﷺ combining of the two prayers at Arafah, that he combined them with one call to prayer and two calls to start the prayer, and nothing contrary to this has come in any established hadith. Combining the two prayers at Muzdalifa is like combining them at Arafah, the two cases differing only in whether the prayers are brought forward or delayed."He said, The view of Ahmad, and of Shafii according to the sounder position reported from him, and of Abu Thawr, Abdul-Malik Majishun, and Tahawi, is that the two prayers are performed with one call to prayer and two calls to start the prayer, and their evidence is the long hadith of Jabir.He said, Malik said, The two prayers are performed with two calls to prayer and two calls to start the prayer, and this is also the view of Ibn Masud. Ibn Munzir said, This has also been reported from Umar . Ibn Abdul-Barr said, "I do not know of this being traced back to the Prophet ﷺ in any way, but it has been reported from Umar bin Khattab that he prayed the two prayers at Muzdalifa in this manner."This ends the statement of Ibn Qayyim, with some rearrangement in it. See Tahzib Sunan (2/400).