Chapter:81 to Verse:23 & 24

he (Muhammad) indeed saw him (Gabriel) in the clear horizon 81:23
And Muhammad is not a withholder of [knowledge of] the unseen. 81:24
Meaning:-
Horizon: the limit or range of a person’s knowledge or understanding.

Chapter:2 to Verse:3, 4 & 5

Who believe in the unseen, establish prayer, and spend out (charity) of what We have provided for them, 2:3
And who believe in (the Quran) what has been revealed to you, [O Muhammad], and what [the Taurat (Torah) and the Injeel (Gospel), etc.] was revealed before you, and of the Hereafter they are certain [in faith]. 2:4
Those are upon [right] guidance from their Lord, and it is those who are the successful. 2:5