Jabir bin Abdullah, when he began the prayer, would raise his hands. He would do the same when he bowed and when he raised his head from bowing. He said, "I saw the Messenger of Allah ﷺ do the same."
عن جابر بن عبد الله، كان اذا افتتح الصلاة رفع يديه، واذا ركع، واذا رفع راسه من الركوع فعل مثل ذلك، ويقول: رايت رسول الله ﷺ فعل مثل ذلك.
Ibn Majah narrated it (868) from Muhammad bin Yahya, who said, Abu Huzaifa narrated to us, who said, Ibrahim bin Tahman narrated to us, from Abu Zubayr, that Jabir bin Abdullah, when he began the prayer, then he mentioned it. Its chain is hasan because of Abu Zubayr.Imam Ahmad narrated it (1433) from Nasr bin Bab, from Hajjaj, from Dhayyal bin Harmala, who said, I asked Jabir bin Abdullah al-Ansari, "How many were you on the day of the Tree?" He said, "About one thousand four hundred." He also said, "The Messenger of Allah used to raise his hands at every takbir of the prayer."Nasr bin Bab al-Khurasani, Abu Sahl al-Marwazi, who settled in Baghdad, was criticized by Bukhari, Ibn Main, Abu Hatim, and others, except that Imam Ahmad saw no harm in him. They only faulted him because he narrated from Ibrahim Sayigh.Hafiz said in Tajil (11/2), "In the Musnad of Jabir from Musnad Ahmad, after narrating a hadith from Nasr bin Bab, he said, Abdullah said, I said to my father, I heard Abu Khaythama, meaning Zuhayr bin Harb, say, Nasr bin Bab is a liar. So he said, I seek forgiveness from Allah, a liar? They only faulted him because he narrated from Ibrahim Sayigh, and Ibrahim was from the people of his town, so it is not implausible that he heard from him." End of quote. Ibn Adi said, "Despite his weakness, his hadith is written down."Hajjaj is Ibn Artah, the judge, one of the jurists, "truthful but made many mistakes and practiced tadlis."In conclusion, the chain of Ahmad is daif, but it strengthens the chain of Ibn Majah regarding the raising of the hands at every takbir, because it is not narrated by Nasr bin Bab from Ibrahim Sayigh. As for the account of the number of the Prophet's companions ﷺ at Hudaybiya, it has been established through sahih chains, which will be discussed in their proper place, Allah willing.