"I asked the Prophet ﷺ about one who prays sitting down. He said: 'Whoever prays standing up is better, and one who prays sitting down will have half the reward of one who prays standing up. And whoever prays lying down will have half the reward of one who prays sitting down.'"  

سَأَلْتُ النَّبِيَّ ﷺ عَنِ الَّذِي يُصَلِّي قَاعِدًا قَالَ مَنْ صَلَّى قَائِمًا فَهُوَ أَفْضَلُ وَمَنْ صَلَّى قَاعِدًا فَلَهُ نِصْفُ أَجْرِ الْقَائِمِ وَمَنْ صَلَّى نَائِمًا فَلَهُ نِصْفُ أَجْرِ الْقَاعِدِ