What is the ruling on forgetting a dhikr (remembrance of God) before an action and remembering it afterward, such as forgetting the dhikr for riding in a car and remembering it after driving? And is it permissible to say it at that point? And is there a reward for reading Islamic books? And does repeating verses of the Quran for memorization earn the reward of a good deed for every letter?

Whoever forgets an invocation (dhikr) prescribed for a specific time may perform it whenever he remembers it, for Al-Nawawi said: "It is befitting for one who has a regular litany (wazifa) of remembrance, and misses it, to make it up when he is able to." The proof for this is the hadith of Umar ibn Al-Khattab (may Allah be pleased with him) that the Messenger of Allah (peace be upon him) said: "Whoever sleeps past his portion (hizb) [of Qur'an] or a part thereof, and recites it between the Fajr prayer and the Dhuhr prayer, it will be recorded for him as if he had recited it during the night."

As for reading books of Sharia with the intention of gaining understanding and learning knowledge, there is much good in it and a great reward, for the Prophet (peace be upon him) said: "Whomever Allah wishes good for, He grants him understanding in religion," and "Whoever treads a path seeking knowledge, Allah will make easy for him a path to Paradise."

Regarding the repetition of a verse or its reiteration for memorization or understanding, the one who repeats a verse is considered a reciter with each repetition. Thus, he earns ten good deeds for every letter each time he repeats the verse or surah, for he (peace be upon him) said: "Whoever recites a letter from the Book of Allah will receive a good deed, and the good deed is multiplied tenfold."