It is narrated from Ibn Ishaq concerning the eminent Companions who took part in the Battle of Badr alongside the Prophet (peace and blessings be upon him): (Among them) was Zayd bin Harithah bin Sharahil al-Kalbi (may Allah be pleased with him), the freed slave of the Messenger of Allah (peace and blessings be upon him).

It is narrated from Urwah that the first person to accept Islam was Zayd bin Harithah (may Allah be pleased with him).

It is narrated from Sayyidah Aishah (may Allah be pleased with her) that when Zayd bin Harithah, Ja'far bin Abi Talib and Abdullah bin Rawahah (may Allah be pleased with them) were martyred, the Messenger of Allah (peace and blessings be upon him) sat down and wept (in grief for them), and signs of sorrow and grief could be clearly recognized on his (peace and blessings be upon him) blessed face.