It is narrated from Hazrat Anas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) once said to Hazrat Ubayy bin Ka'b (may Allah be pleased with him) that Allah has commanded me to recite to you the Surah "Alam Yakunilladhina Kafaru". Hazrat Ubayy bin Ka'b (may Allah be pleased with him) asked, "Did Allah mention me by name?" The Prophet (peace and blessings be upon him) replied, "Yes!" Upon hearing this, Ubayy bin Ka'b (may Allah be pleased with him) began to weep.