Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
bayhaqi:4593 – Abū Bakr b. Fūrak > ʿAbdullāh b. Jaʿfar > Yūnus b. Ḥabīb > Abū Dāwud al-Ṭayālisī > Shuʿbah > Manṣūr > Hilāl b. Yasāf > Abū Yaḥyá al-Aʿraj > ʿAbdullāh b. ʿAmr

[Machine] The Messenger of Allah ﷺ said: "The sitting prayer is equivalent to half of the standing prayer."  

البيهقي:٤٥٩٣ – أنبأ أَبُو بَكْرِ بْنُ فُورَكٍ أنبأ عَبْدُ اللهِ بْنُ جَعْفَرٍ ثنا يُونُسُ بْنُ حَبِيبٍ ثنا أَبُو دَاوُدَ الطَّيَالِسِيُّ ثنا شُعْبَةُ عَنْ مَنْصُورٍ قَالَ سَمِعْتُ هِلَالَ بْنَ يَسَافٍ يُحَدِّثُ عَنْ أَبِي يَحْيَى الْأَعْرَجِ عَنْ عَبْدِ اللهِ بْنِ عَمْرٍو

أَنَّ رَسُولَ اللهِ ﷺ قَالَ صَلَاةُ الْقَاعِدِ عَلَى النِّصْفِ مِنْ صَلَاةِ الْقَائِمِ  

أَخْرَجَهُ مُسْلِمٌ مِنْ حَدِيثِ غُنْدَرٍ عَنْ شُعْبَةَ وَفِي حَدِيثِ جَرِيرٍ عَنْ مَنْصُورٍ تَخْصِيصُ النَّبِيِّ ﷺ بِالصَّلَاةِ جَالِسًا وَأَنَّ قَوْلَهُ صَلَاةُ الْقَاعِدِ عَلَى النِّصْفِ مِنْ صَلَاةِ الْقَائِمِ فِي غَيْرِهِ وَذَلِكَ يَرِدُ إِنْ شَاءَ اللهُ تَعَالَى فِي بَابِ الْخَصَائِصِ فِي أَوَّلِ كِتَابِ النِّكَاحِ

See similar narrations below:

Collected by Mālik
malik:8-20 – Yaḥyá > Mālik > Ismāʿīl b. Muḥammad b. Saʿd b. Abū Waqqāṣ > a freed slave of Liʿamriw b. al-ʿĀṣ Aw Liʿabd Allāh b. ʿAmr b. al-ʿĀṣ > ʿAbdullāh b. ʿAmr b. al-ʿĀṣ

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 ﷺ said, "The prayer of one of you sitting down is only equal to half the prayer of one of you when he is standing."  

مالك:٨-٢٠ – حَدَّثَنِي 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 ﷺ قَالَ صَلاَةُ أَحَدِكُمْ وَهُوَ قَاعِدٌ مِثْلُ نِصْفِ صَلاَتِهِ وَهُوَ قَائِمٌ