Jami` at-Tirmidhi 170
جامع الترمذي#170Sahihحَدَّثَنَا أَبُو عَمَّارٍ الْحُسَيْنُ بْنُ حُرَيْثٍ، حَدَّثَنَا الْفَضْلُ بْنُ مُوسَى، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ الْعُمَرِيِّ، عَنِ الْقَاسِمِ بْنِ غَنَّامٍ، عَنْ عَمَّتِهِ أُمِّ فَرْوَةَ، وَكَانَتْ، مِمَّنْ بَايَعَتِ النَّبِيَّ صلى الله عليه وسلم قَالَتْ سُئِلَ النَّبِيُّ صلى الله عليه وسلم أَىُّ الأَعْمَالِ أَفْضَلُ قَالَ " الصَّلاَةُ لأَوَّلِ وَقْتِهَا " .
Umm Farwah - and she was one of those who gave pledge of allegiance to the Prophet - narrated:"The Prophet was asked: 'Which deed is the best?' So he said: 'Salat in the beginning of its time
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 2:22