Sahih Muslim , Book 1, Hadith 162 (In-Book) ⓘ
It is reported on the authority of 'Abdullah that the Messenger of Allah observed: The best of' the deeds or deed is the (observance of) prayer at its proper time and kindness to the parents.
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا جَرِيرٌ، عَنِ الْحَسَنِ بْنِ عُبَيْدِ اللَّهِ، عَنْ أَبِي عَمْرٍو الشَّيْبَانِيِّ، عَنْ عَبْدِ اللَّهِ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " أَفْضَلُ الأَعْمَالِ - أَوِ الْعَمَلِ - الصَّلاَةُ لِوَقْتِهَا وَبِرُّ الْوَالِدَيْنِ " .
also referenced under: Hadith 85 (Reference) & Book 1, Hadith 155 (USC-MSA)