What is the difference between supplicating with Allah's Greatest Name and other forms of supplication? Is its answer immediate or is it linked to the removal of impediments? And why did scholars favor that it is the لفظ الجلالة (word of majesty, i.e., Allah) despite its absence in His saying, "And your God is one God"? Is it a prerequisite for the one who supplicates with it to have prior knowledge and certainty of it?

Supplicating with the Greatest Name is more likely to be answered. It is not a condition for the supplicant to know that it is the Greatest Name. The preponderant opinion is that the majestic name "Allah" is the Greatest Name, due to its mention in most of the hadiths that speak about the Greatest Name.

Many scholars, including Al-Khatib Al-Shirbini, Ibn Abidin, and Al-Qurtubi, believe that "Allah" is the Greatest Name. This does not contradict the hadiths that mention specific verses like "And your god is one God. There is no deity except Him, the Most Merciful, the Especially Merciful" and "Alif, Lam, Meem. Allah - there is no deity except Him, the Ever-Living, the Sustainer of existence"; because the majestic name is explicitly mentioned in the verse from Al-Imran, and in the verse from Al-Baqarah, the description of divinity, whose origin is "Ilah (God)," is mentioned.

The reason why many people's supplications are not answered when using the Greatest Name is due to their failure to meet the conditions and etiquettes of supplication, and the presence of obstacles to its acceptance.