Surah Yunus, Ayat 12

Ayat 12. And when harm touches man, he invokes Us, lying down on his side, or sitting or standing. But when We have removed his harm from him, he passes on his way as if he had never invoked Us for a harm that touched him! Thus it seems fair to the Musrifun (ungrateful, one who exceed his limits) that which they used to do. 

Hazrat Abdullah bin Amr bin Al-as (May Allah be pleased with him) reported: Messenger of Allah [SAWW](PBUH) said to me, "O 'Abdullah! Do not be like so-and-so; he used to get up at night for (Tahajjud) optional prayer but abandoned it later.'' [Al-Bukhari Hadith # 1152].

Lesson : as mentioned above in Surah Yunus Ayat 12. when We have removed his harm from him, he passes on his way as if he had never invoked Us for a harm that touched him!. This Hadith also stresses the same point as Ayat 12, that is, man should be grateful to Allah and steadfast in his good doings. There should be no cessation in this respect, otherwise, he will unconsciously begin to incline to evil and, therefore, to the erosion of moral foundations of his character. Steadfastness in the observance of good ensures man's security against pitfalls and has Divine approval, too