One day We shall raise from all Peoples a witness against them, from amongst themselves: and We shall bring thee as a witness against these (thy people): and We have sent down to thee the Book explaining all things, a Guide, a Mercy, and Glad Tidings to Muslims.
The Qur’an explains Everything
(And We revealed the Book (the Qur’an) to you as an
explanation of everything,) Ibn Mas`ud said: “Allah﴾
made it clear that in this Qur’an there is complete
knowledge and about everything.” The Qur’an contains
all kinds of beneficial knowledge, such as reports of what
happened in the past, information about what is yet to
come, what is lawful and unlawful, and what people need
to know about their worldly affairs, their religion, their
livelihood in this world, and their destiny in the
means, for their hearts.
a mercy, and good news for the Muslims.
And We have revealed the Book (the Qur’an) as an explanation of everything),
meaning, with the Sunnah. That is the reason why the phrase, And We have revealed the Book to you), is mentioned immediately after the phrase,
And We shall bring you (O Muhammad) as a
witness against these.
the meaning – and Allah knows best – is
that the One Who obligated you to convey
the Book which He revealed to you, will
also ask you about that on the Day of
Then We shall indeed question those (people) to
whom it (the Book) was sent and We shall indeed
question the Messengers. (7:6)
So by your Lord We question them all about what
they did. (15:92-92)
On the Day when Allah gathers the Messengers
together and says to them: “What was the
response you received (to your Message)!”
They will say: “We have no knowledge, indeed
only You are the Knower of all that is hidden.”
And Allah says:
Verily, He Who obligated the Qur’an upon you (O
Muhammad) will surely bring you back to the
meaning, the One Who gave you the
obligation of conveying the Qur’an will
bring you back to Him, and your return will
be on the Day of Resurrection, and He will
question you about you commission of the
duty He gave you.
This is one of the opinions, and it presents
a good understanding of it.
Kathir, Ibn. Tafsir Ibn Kathir. (Surah 16 verses 89). https://ia803208.us.archive.org/22/items/TafseerIbnKathirenglish114SurahsComplete/002BaqarahI.pdf