Tafsir of Al-Balad 90:7

Does he think that no one has seen him? That is: when he was spending what he spent, either to be seen by people or out of an intense desire to oppose the Prophet—may Allah’s peace and blessings be upon him. This means that Allah—Exalted be He—was seeing him and was—Glorified be He—an observer over him. He—Almighty and Majestic is He—will ask him about it and recompense him for it. In the Hadith: "The feet of a servant shall not move on the Day of Resurrection until he is asked about four things: his life, how he spent it; his wealth, from where he earned it and on what he spent it; and his knowledge, what he did with it."

It has also been suggested that the meaning is: "Does he think that no one will find him?" based on the understanding that "seeing" implies the discovery that necessarily accompanies it, and that lam (did not) here signifies lan (will not). It was expressed this way to emphasize that the occurrence is certain—meaning that Allah—Exalted be He—will find him on the Day of Resurrection and call him to account for that.

Al-Kalbi stated that this claimant was a liar who had not spent anything at all. Thus, Allah—Exalted be He—said: Does he think that Allah—Exalted be He—did not see that from him, whether he did or did not do it, whether he spent or did not spend? Rather, He—Almighty and Majestic is He—saw it and knew that the truth was contrary to what he claimed. He—Glorified be He—confirmed the power to recompense him and the omniscience regarding his state with His saying—Exalted and Majestic is He—...