Tafsir of Qaf 50:21

And every person will come forth along with a Sa'iq and a Shahid. meaning, an angel to drive him to the gathering place and an angel to bear witness against him with regards to his deeds. This is the apparent meaning of this honorable Ayah and it is the meaning that Ibn Jarir preferred. It was narrated from Yahya bin Rafi`, the freed servant of Thaqif, that he heard Uthman bin Affan, may Allah be pleased with him, giving a speech in which he recited this Ayah,

وجاءت كل نفس معها سايق وشهيد

(And every person will come forth along with a Sa'iq and a Shahid), and then said, "A Sa'iq to drive every person to Allah the Exalted, and a Shahid to witness against him what he has done.'' The statement of Allah the Exalted,

لقد كنت في غفلة من هذا فكشفنا عنك غطاءك فبصرك اليوم حديد