Harmalah, the freed slave of Sayyiduna Usamah bin Zayd (may Allah be pleased with him), narrates that once he was sitting with Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) when al-Hajjaj bin Ayman, the son of Umm Ayman, came in. He was a man of the Ansar, and Ayman was the elder brother of Sayyiduna Usamah bin Zayd (may Allah be pleased with him). Harmalah says: Al-Hajjaj offered a prayer in which he did not complete his bowing and prostrations. When he said the salam, Sayyiduna Ibn Umar (may Allah be pleased with them both) called him and said: "O my nephew, do you think that you have prayed? Your prayer has not counted; repeat your prayer." When al-Hajjaj had gone, Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said to me: "Who was this?" I said: Al-Hajjaj bin Ayman, the son of Umm Ayman. Sayyiduna Ibn Umar (may Allah be pleased with them both) said: "Had the Messenger of Allah (peace and blessings be upon him) seen him, he would have loved him." Then he mentioned the reason for that love: that he was among the offspring of Umm Ayman (may Allah be pleased with her), and Umm Ayman (may Allah be pleased with her) was the one who nursed and cared for the Prophet (peace and blessings be upon him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3999