Is it necessary to say "Bismillah" when performing ablution to ward off obsessive thoughts, and is a heartfelt intention sufficient, or is it enough to bring it to mind before entering the bathroom? Do the Adhan and Iqama constitute a sufficient intention to begin prayer directly with the opening Takbir, and is ablution itself considered an intention for prayer?

We advise those who suffer from obsessive whispers (waswasah) to ignore them. As for saying Bismillah before ablution, the majority of scholars hold that it is a Sunnah (definition) and not a condition. It is the utterance of "Bismillah," and not the intention (niyyah (definition)). As for the intention for prayer, there is no harm in making it before the takbirat al-ihram (definition). The intention is simple; whoever performs ablution for prayer or performs the iqamah (definition) for it has intended the prayer. Intention follows knowledge, so whoever knows what they intend to do has already intended it.