Reference: Fataawa Noor ‘alad-Darb – Question No.6315, Page 153, Volume 12
Question: One of the conditions of the supplication is to repeat it three times, and after the khutbah on the day of Jumu’ah, the imaam made the supplication only once – so is that permissible?
Response: The matter is not as this brother has understood, that from the conditions of supplicating is to repeat it three times; rather this is from the etiquettes – which is not a condition.
And it is permissible for a person to supplicate to Allaah (Ta’aala) once without repeating the supplication; so repeating it is [merely] a matter of etiquette and not a condition.
