The freed slave of Usama bin Zaid said, "Al-Hajjaj bin Aiman bin Um Aiman and Aiman Ibn Um Aiman was Usama's brother from the maternal side, and he was one of the Ansar. He was seen by Ibn 'Umar not performing his bowing and prostrations in a perfect manner. So Ibn 'Umar told him to repeat his prayer.
Hadith Referenceصحيح البخاري / كتاب فضائل الصحابة / 3736
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة
Harmala, the freed slave of Usama bin Zaid said that while he was in the company of 'Abdullah bin 'Umar, Al-Hajjaj bin Aiman came in and (while praying) he did not perform his bowing and prostrations properly. So Ibn 'Umar told him to repeat his prayer. When he went away, Ibn 'Umar asked me, "Who is he?" I said, "Al-Hajjaj bin Um Aiman." Ibn 'Umar said, "If Allah's Apostle saw him, he would have loved him." Then Ibn 'Umar mentioned the love of the Prophet for the children of Um Aiman. Sulaiman said that Um Aiman was one of the nurses of the Prophet.
Hadith Referenceصحيح البخاري / كتاب فضائل الصحابة / 3737
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة
Narrated Harmala: (Usama's Maula) Usama (bin Zaid) sent me to `Ali (at Kufa) and said, "`Ali will ask you, 'What has prevented your companion from joining me?' You then should say to him, 'If you (`Ali) were in the mouth of a lion, I would like to be with you, but in this matter I won't take any part.' " Harmala added: "`Ali didn't give me anything (when I conveyed the message to him) so I went to Hasan, Hussain and Ibn Ja`far and they loaded my camels with much (wealth).
Hadith Referenceصحيح البخاري / كتاب الفتن / 7110
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة