Hadithcore
Mishkat al-Masabih, 1058

Abu Huraira reported God’s Messenger as saying, “When the time for prayer comes, only the prescribed prayer is to be said.” Muslim transmitted it.

وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا أُقِيمَتِ الصَّلَاةُ فَلَا صَلَاةَ إِلَّا الْمَكْتُوبَة» . رَوَاهُ مُسلم

References1 variant
In-Book Reference
Book 4, Hadith 476