Assalaamu alaykum. My question is about guidance.
A) Are there surahs or supplications that block sins?
B) Does reading Surat Al-Kafiroon before sleeping make us immune to Shirk (polytheism)? Should we immediately go to sleep after reciting it, or can we recite others surahs and supplications after it also? Does it protect from major Shirk, minor Shirk, or both?
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
We have not come across any specific verse or supplication that prevents committing sins, but the entire Quran is helpful in asking Allah for whatever a person wishes.
The hadeeth reported by At-Tirmithi reads, "Whoever recites the Quran, let him ask Allah with it."
After reporting the hadeeth, he said, "It is a Hasan (good) hadeeth." Al-Albaani also classified it as Hasan.
As for the recitation of Soorah Al-Kaafiroon [Quran 109], then one should recite it as the last thing before sleeping, as it includes disassociating oneself from every kind of Shirk.
The Prophet said, "Recite when you go to sleep {Say, "O disbelievers...} [Quran 109]; and then go to sleep at its end, for it is disassociating oneself from Shirk." [Ahmad; Al-Arna‘oot: Hasan; Abu Daawood; Al-Albaani: Saheeh (sound)]
Al-Munaawi said in At-Tayseer bi-Sharh Al-Jaami‘ As-Sagheer (1/62), "(Then go to sleep at its end) means recite it in full and make it the last thing you say and then sleep, as the above mentioned Soorah is a disassociation from polytheism, i.e. it includes declaring oneself free from Shirk, which is the worship of idols, as the first two verses are a negation of worshipping what the polytheists worship at the present time and the last two verses are a negation of this act in the future."
Shaykh Ibn Taymiyyah said, "It is known that what is meant is disassociation from every kind of Shirk, whether it is in belief or in action."
Allah knows best.
You can search for fatwa through many choices