In the invaluable books ‘Al-Kafi’...
In the invaluable books ‘Al-Kafi’, ‘Tawhid Saduq’, ‘Ma’ani Al-Akhbar’ and ‘Tafsir Ayyashi’, it is narrated from Imam Sadiq (as): “Each of these three letters (in the word ‘ bism ’) implies one of the Glorious names of Allah; ‘ ba' ’ is Allah’s Brightness , ‘ sin ’ is Allah’s Eminence, and ‘ mim ’ is His Magnificence. It is also stated that ‘ ba' ’ implies the Observant , ‘ sin ’ implies the All-Hearing, and ‘ mim ’ implies the Counter.
It is as if Allah makes the supplicant aware that: I am the Observant; I can observe your visible and invisible deeds, so avoid hypocrisy in your action, I am the All-Hearing; I can hear the result of your deeds and supplications, so avoid useless speech, and I am the Counter; I can even count your breaths, so beware of every moment. The glorified word ‘ Allah ’ is a comprehensive name for the Almighty, which is a combination of all the attributes of Allah.
It is believed that three meanings are present in Allah: Allah is the Eternal Being. Human mind is astonished of knowing and seeking Him. The return of all beings is towards Him. It is said that the Arabic word ‘الله ( Allah )’ is the Chief name of God and is the basis of His Unity, to that extent that if a disbeliever calls this name sincerely, his belief will be proved. This name is the beginning and end of everything, which is to be upright.
Also the strength of risalat (prophet hood) and wilayat is based on this name, as it exists in the Arabic phrase ‘محمد رسول الله ( Muhammad is Allah’s Messenger )’ and ‘علي ولي الله ( ‘Ali is Allah’s Intimate Servant )’. Furthermore, if the first letter of the Arabic word ‘A llah (الله)’ is omitted, what remains is ‘ lillahi (لله)’, which means ‘for Allah,’ as in the following Verse: لِلَّهِ الأَمْرُ مِنْ قَبْلُ وَمِنْ بَعْدُ. Allah's is the command before and after.
(30:4) If the first two letters are dropped, what remains is ‘ lahu (له)’, which means (His) remains, as in the following Verse: لَهُ الْمُلْكُ وَلَهُ الْحَمْدُ. To Him belongs the kingdom, and to Him is all due praise. (64:1) If the first three letters are dropped, what remains is ‘ huwa (هو)”, which means ‘He’ implying Almighty Allah, as in the following Verse: قُلْ هُوَ اللَّهُ أَحَدٌ. Say: He, Allah, is One.
(112:1) As a result, the name, which has so many features, is definitely Allah’s Chief name. The word “رحمن” (the Beneficent) is derived from “رحمت” (Mercy). Renowned Arab grammarians believe that it is a hyperbole.