﴿ حَتَّىٰٓ إِذَا جَآءُو قَالَ أَكَذَّبْتُم بِـَٔايَٰتِى وَلَمْ تُحِيطُوا۟ بِهَا عِلْمًا أَمَّاذَا كُنتُمْ تَعْمَلُونَ ﴾

“until such a time as they shall come [to be judged. And] He will say: “Did you give the lie to My messages even though you failed to encompass them with [your] knowledge? Or what was it that [you thought] you were doing?””

until when they arrive at the site of the Reckoning He exalted be He shall say to them ‘Did you deny My prophets by denying My signs without comprehending them from the perspective of your denial in knowledge or what ammā the interrogative mā has been assimilated with am ‘or’ was it dhā is a relative pronoun in other words it is in fact mā alladhī that you did? with the commands given to you.