Sayyiduna Ibn Abbas (may Allah be pleased with them both) said about the saying of Allah Almighty: "And when they hear what has been revealed to the Messenger, you see their eyes overflowing with tears": "These people were nawwanin, that is, sailors, who had come from Abyssinia with Sayyiduna Ja'far bin Abi Talib (may Allah be pleased with him). When the Messenger of Allah (peace and blessings be upon him) recited the Noble Qur'an to them, they believed and their eyes overflowed with tears. Then the Messenger of Allah (peace and blessings be upon him) said: 'Perhaps when you return to your land you will turn away from your religion?' They said: 'We will never turn away from our religion.' So Allah Almighty revealed this (verse) in connection with that saying of theirs."
Imam al-Tabarani (may Allah have mercy on him) said: "Only Abd al-Jabbar bin Nafi' narrated this hadith from Qatadah and Abu Bishr (Ja'far bin Iyas, may Allah have mercy on him), and Abbas bin Fadl is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب العين / 4639
Hadith Takhrij«أخرجه الضياء المقدسي فى «الأحاديث المختارة» برقم: 362، والطبراني فى «الكبير» برقم: 12455»