Majma al-Zawaid — Hadith 9840

Abdullah bin Amir bin Rabi'ah narrates the statement of his mother, Sayyidah Layla (may Allah be pleased with her): With regard to our accepting Islam, Sayyiduna Umar (may Allah be pleased with him) was our harshest opponent. When we intended to go to the land of Abyssinia, Sayyiduna Umar (may Allah be pleased with him) came (he was not a Muslim at that time). I was mounted on my camel, intending to set off on the journey. He asked: "O Umm Abdullah, where are you going?" I replied: "You people harm us because of our religion, so we are going out into Allah's earth so that we are not harmed for worshipping Allah Almighty." Sayyiduna Umar (may Allah be pleased with him) said: "May Allah Almighty be with you." Then he went away. Later my husband, Amir bin Rabi'ah, came and I told him about the tenderness of Sayyiduna Umar (may Allah be pleased with him). He said: "Do you expect that he will become a Muslim?" I replied: "Yes." He said: "By Allah! He will not become a Muslim until the donkey of (his father) al-Khattab becomes a Muslim."
Al-Tabarani recorded it. Ibn Ishaq has explicitly stated that he heard it directly, and this report is sahih (authentic).