﴿ لِّيُنذِرَ مَن كَانَ حَيًّۭا وَيَحِقَّ ٱلْقَوْلُ عَلَى ٱلْكَٰفِرِينَ ﴾

“to the end that it may warn everyone who is alive [of heart], and that the word [of God] may bear witness against all who deny the truth.”

that he may warn li-yundhira; or read li-tundhira ‘that you may warn’ therewith whoever is alive able to comprehend what is being said to him — and such are the believers — and that the Word of chastisement from God may be fulfilled against the disbelievers who are like the dead unable to comprehend what is said to them.