Hadith 1759
Abu Hurairah (May Allah be pleased with him) said:
عن أبي هريرة رضي الله عنه عن النبي صلى الله عليه وسلم قال: "إذا أقيمت الصلاة، فلا صلاة إلا المكتوبة" ((رواه مسلم)).
The Prophet (ﷺ) said, "When the Iqamah is called, no prayer should be performed except the obligatory prayer." [Muslim].
In plain words
The Prophet taught that once the call to stand for the obligatory prayer is made, no other prayer should be started. When the Iqamah sounds, readiness for the obligatory prayer comes first.
Reference : Riyad as-Salihin 1759 In-book reference : Book 17, Hadith 249