Will this question be directed to the Messengers, or to those whom these Messengers had been sent to? The answer: It will be used as a proof against mankind and not against the Messengers (PBUT).

(… فَيَقُولُ مَاذَا أُجِبْتُمْ… ) (…and say, “What was the response you received?” …): That is: what did the people reply to you? The day on which this will happen is the Last Day; The Day of Judgement, the Day when all of mankind will stand in front of Allah (swt) Lord of the universe. On this day, Allah (swt) will gather all of creation, together with the Messengers. He will say: “What was the response you received?”, i.e., “What was the response from mankind with regards to the messages you sent to them from Me?” In the answer given by the Messengers, observe their good manners towards Allah (swt), which was obtained from their faith, and also the precision of the answer:

(  قَالُوا لَا عِلْمَ لَنَا ۖ إِنَّكَ أَنتَ عَلَّامُ الْغُيُوبِ … ) (…They will say, “We have no knowledge. Indeed, it is You who is Knower of the unseen”.): Why do they give this answer? It is because, that having faith in Allah (swt) and belief in the Messengers are dependent on the intentions, as the Prophet (saws) has said:

“Actions are but by intentions, and indeed each person will have that which he intended.”[1]

Therefore, there could be many hypocrites, or there could also be people who repented nearing death. Thus, they answered: “We have no knowledge. Indeed, it is You who is Knower of the unseen“. Only Allah (swt) knows the unseen, and the secrets and what is hidden. Even if they knew a part of it, He knows it fully. He knows the intentions of those of mankind who had obeyed His messages brought to them by the Messengers. The above demonstrates the accuracy of the answers given by the Messengers (PBUT), obtained from their deep faith.

[1] Sunan abi Dawood: Book of Divorce, Chapter of what the is intended by the Divorce and the intentions, Hadith No. 2201.