Muwatta Malik 306
موطأ مالك#306Sahihحَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ إِسْمَاعِيلَ بْنِ مُحَمَّدِ بْنِ سَعْدِ بْنِ أَبِي وَقَّاصٍ، عَنْ مَوْلًى، لِعَمْرِو بْنِ الْعَاصِ - أَوْ لِعَبْدِ اللَّهِ بْنِ عَمْرِو بْنِ الْعَاصِ - عَنْ عَبْدِ اللَّهِ بْنِ عَمْرِو بْنِ الْعَاصِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " صَلاَةُ أَحَدِكُمْ وَهُوَ قَاعِدٌ مِثْلُ نِصْفِ صَلاَتِهِ وَهُوَ قَائِمٌ " .
Yahya related to me from Malik from Ismail ibn Muhammad ibn Said ibn Abi Waqqas from a mawla of Amr ibn al-As or of Abdullah ibn Amr ibn al-As that the Messenger of Allah, may Allah bless him and grant him peace, said, "The prayer of one of you sitting down is only equal to half the prayer of one of you when he is standing
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: 8:20