Tafsir of Fussilat 41:50

"And if We let him taste mercy from Us after adversity which has touched him"—meaning, if We relieve him with health after sickness, or prosperity after hardship, or other than that—"he will surely say, 'This is mine'"—meaning: "It is my right; I deserve it due to the merit and works I possess, not by the grace of Allah, the Exalted and Majestic." Thus, the lam (in li) denotes entitlement. Alternatively, it may mean: "It is mine permanently and shall not cease," in which case the lam denotes ownership, implying perpetuity. Perhaps the first interpretation is closer.

"And I do not think the Hour will be established"—meaning, that it will occur in the future. "And if I should be returned to my Lord"—upon the assumption of its occurrence—"indeed, there will be for me with Him the best"—meaning, the best state of honor.

The emphasis here through the oath is not for the establishment of the Hour, but rather for the fact that he will be rewarded with the best, due to his conviction that he deserves honor. This is because he believes that the worldly blessings he received were due to his own merit, and that the blessings of the Hereafter would likewise be so. Thus, there is no contradiction between the particle inna—which in principle is used for that which is not certain—and the emphasis by oath, nor between the lam, the precedence of the two prepositional phrases, and the superlative form.

"Then We will surely inform those who disbelieved about what they did"—meaning, We will make them know the reality of their deeds and show them the opposite of what they believed regarding them. It will become clear to them that they are deserving of humiliation, not honor, as they had imagined.

"And We will surely make them taste a severe punishment"—one from which they cannot escape due to its intensity; it is like a thick shackle that cannot be broken.