﴿ هَٰذَا نَذِيرٌۭ مِّنَ ٱلنُّذُرِ ٱلْأُولَىٰٓ ﴾

“THIS IS a warning like those warnings of old:”

(This is a warner) i.e. Muhammad (pbuh) is a warning Messenger (of the warners of old) like the earlier messengers whom We sent to their folks; it is also said that this means: this is a messenger among the messengers of old whom it is written, in the Guarded Tablet, that We would sent to their folks.