Tafsir of Al-An'am 6:30

{And if you could see when they are made to stand before their Lord} This is a metaphor for being detained for the purpose of rebuke and questioning, just as a guilty slave is made to stand before his master to be reprimanded. It is also said: they are made to stand before the recompense of their Lord. Others say: they have come to know Him with true knowledge.

{He will say} This is a response to one who asks: "What did their Lord say to them when they were made to stand before Him?" It is said: He will say, {Is this not the truth?} This is a reproach from Allah, the Exalted, regarding their denial and their previous claims—whenever they heard talk of resurrection and recompense—that it was not the truth, but rather falsehood.

{Because you used to disbelieve} Meaning: because of your disbelief in meeting Allah, the arrival of the Hereafter, and all that pertains to it. This has been thoroughly discussed in other places.

{Until} This is the limit for "they denied," not for "loss," because their loss has no limit. That is, their denial continued until their regret at the time the Hour arrives.

If you ask: Do they not regret at the time of their death? I say: Since death is an entry into the states of the Hereafter and its preliminaries, it is treated as being of the same nature as the Hour and is called by its name. That is why the Messenger of Allah (ﷺ) said: "Whoever dies, his resurrection has begun." Or, the arrival of the Hour is placed after death because of its swiftness, as if it occurs without a pause.

{Suddenly} Meaning: unexpectedly. It is in the accusative case as a state (hal), meaning "taking them by surprise," or as an infinitive (masdar), as if it were said: "The Hour surprised them with a surprise."

{We neglected it} The pronoun refers to the worldly life. It is used even though it was not previously mentioned because it is understood. Alternatively, it refers to the Hour, meaning: we were negligent regarding it and regarding belief in it, just as one says: "I was negligent regarding so-and-so." From this is: "I was negligent regarding the side of Allah."

{They will bear their burdens on their backs} This is like His saying: "Because of what your hands have earned," because it is customary to carry heavy loads on the back, just as it is customary to earn with the hands.

{Evil is that which they bear} Meaning: how wretched is the thing they bear as their burden, similar to His saying: "Evil is the example of the people."

{And the worldly life is not but amusement and diversion; but the home of the Hereafter is best for those who fear Allah, so will you not then reason?}