﴿ وَلَوْ جَآءَتْهُمْ كُلُّ ءَايَةٍ حَتَّىٰ يَرَوُا۟ ٱلْعَذَابَ ٱلْأَلِيمَ ﴾

“even though every sign [of the truth] should come within their ken - until they behold the grievous suffering [that awaits them in the life to come].”

(Though every token) they asked you to provide (come unto them) they will not believe, (till they see the painful doom) the Day of Badr, Uhud and the day of the confederates.