(So who henceforth) i.e. after what I have mentioned to you of the transformation of youth and old age, life and death (will give the lie to thee) O Muhammad (about the judgement) about the Day of Reckoning? It is also said this means: what has driven you, O Kildah Ibn Usayd and Walid Ibn al-Mughirah, to deny the Day of Judgement?