عَنْ مُجَاهِدٍ أَنَّ السَّائِبَ سَأَلَ عَائِشَةَ فَقَالَ: إِنِّي لَا أَسْتَطِيعُ أَنْ أُصَلِّيَ إِلَّا جَالِسًا، فَكَيْفَ تَرَيْنَ؟ قَالَتْ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَقُولُ: ((صَلَاةُ الرَّجُلِ جَالِسًا مِثْلُ نِصْفِ صَلَاتِهِ قَائِمًا))
Saib asked Sayyida Aisha (may Allah be pleased with her) that I am only able to perform prayer while sitting; what is your opinion about this? She said: I heard the Messenger of Allah (peace and blessings be upon him) say: A man's prayer performed while sitting is half of that performed while standing, that is, in terms of reward and merit.