‘Ali bin Abi Talhah reported that Ibn ‘Abbas commented on the Ayah:

“Alas for mankind!”, this means, woe to mankind!
Qatadah said:

“Alas for mankind!” means, “Alas for mankind, who have neglected the command of Allah.”

The meaning is that they will feel regret and sorrow on the Day of Resurrection. When they see the punishment with their own eyes; they will regret how they disbelieved the Messengers of Allah and went against the commands of Allah, for they used to disbelieve in them in this world.

“There never came a Messenger to them but they used to mock at him.”

means, they disbelieved him and made fun of him, and rejected the message of truth with which he had been sent.

The Refutation of the Belief in the Transmigration of Souls

Then Allah says:

“Do they not see how many of the generations We have destroyed before them? Verily, they will not return to them.”

meaning, ‘do they not learn a lesson from those whom Allah destroyed before them of those who disbelieved His Messengers? They came to this world only once, and will not return to it.’ It is not as many of those ignorant people who believe in the transmigration of souls claim, that they will return to this world. They believe that they will come back to this world time after time. Allah is refuting their false claims by saying:

“Verily, they will not return to them.” Allah says:

“And surely, all - everyone of them will be brought before Us.”

meaning, all of the past nations and those that are yet to come, will be gathered and brought to account before Allah, may He be glorified and exalted, on the Day of Judgement, and they will be requited according to their good and evil deeds. This is like the Ayah:

“And there is none of them, but shall come to the Most Gracious as a slave.” (19:93)