Al-Sadiq said: The letter ba' [of the bismilllah] is the glory of God (baha' allah), the sin ("s"), is the splendour of God (sana' allah), and the mim ("m") is the sovereignty of God, mulk Allah). Allah is the God of all things. al-Rahman pertains to creation in general while al-Rahim specifically applies to the believers.
The bismillah is also considered a prayer in its own right, a source of divine knowledge and healing. It is said to contain, in addition to all the knowledge in the Qur'an itself, all the knowledge of the previous scriptures. It has been seen as a means of salvation and protection.