He said he asked the Prophet about a man who prays sitting, and he replied, “If he prays standing that is more excellent; but one who prays sitting has half the reward of one who stands, and one who prays lying down has half the reward of one who sits.” Bukhari transmitted it.
Hadith Referenceمشكوة المصابيح / كتاب الصلاة / 1249
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه البخاري (1116)»