Q.The person is saying: I used to perform many actions of shirk, but Allaah has guided me. Should I ask Allaah to forgive me for those actions which I previously performed?
A.The shaykh (haafidhahullaah) said, you should ask Allaah, you should be diligent in asking Allaah to forgive you for those actions. But you should know that if a person makes sincere, genuine repentance then this would wipe away the actions of shirk. If a person repents from shirk with a sincere, genuine repentance this would wipe away the actions of shirk. But if you combine between asking Allaah to forgive you and making the sincere tawbah, this is better and more preferred.
Shaykh Saalih Muhammad al-Luhaydaan (May Allaah preserve him) (Kitaab-ut-Tawheed Class, Q&A Session 06-10-2012, Riyadh)