What is the meaning of the Almighty's saying, "They forgot Allah, so He made them forget themselves," and how did He make them forget themselves?

Ibn Kathir said in his interpretation of the verse: "And be not like those who forgot Allah, so He made them forget themselves" means do not forget the remembrance of Allah, for that will make you forget to work for the benefit of yourselves, which will profit you in your return.

Al-Shawkani said: "They forgot Allah" means they abandoned His command, or they did not appreciate Him as He should be appreciated, or they did not fear Him. So, "He made them forget themselves" means He made them forget themselves because of their forgetting Allah, so they did not do what would save them from punishment or refrain from sins. The meaning is He made them forget the benefits of themselves. It was also said: they forgot Allah in ease, so He made them forget themselves in hardship.