´It was narrated that Abu Hurairah said:` "The Messenger of Allah (ﷺ) aid: 'When the Iqamah for prayer is said, there is no prayer except the prescribed prayer."'
Hadith Referenceسنن نسائي / كتاب الإمامة / 866
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح مسلم
´It was narrated that Ibn Buhainah said:` "The Iqamah for Subh prayer was said, and the Messenger of Allah (ﷺ) saw a man praying while the Mu'adhdhin saying the Iqamah. He said: 'Are you praying Subh with four Rak'ahs?"'
Hadith Referenceسنن نسائي / كتاب الإمامة / 868
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:متفق عليه