What is the secret behind the word "messages" (رسالات) being in the plural form in reference to Noah, Hud, and Shu'ayb (peace be upon them), and in the singular form "message" (رسالة) in reference to Salih (peace be upon him), and not being mentioned in either the singular or plural form in reference to Lot (peace be upon him) in Surat Al-A'raf?

The word "risālah" (message) is used in the plural when attributed to some prophets like Noah, Hud, and Shu'ayb, and in the singular when attributed to Salih. This could be due to the multiplicity of what they were commanded to convey, or a difference in meanings, or because the singular noun, when added, encompasses all of them. The verse: "And if you do not, then you have not conveyed His message" has been recited in both the singular and plural forms. Some scholars have pointed out that Salih's exclusive use of the singular might be due to his story's focus on the she-camel as a single message. As for Lot, the Quran does not mention that he said this statement to his people.