Prayer at Night - Section 1 Mishkat al-Masabih 1198
Arabic hadith text
وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: لَمَّا بَدَّنَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَثَقُلَ كَانَ أَكْثَرُ صَلَاتِهِ جَالِسًا
Translation
‘A’isha said, “When God’s Messenger grew old and was ill, he mostly prayed sitting.” (Bukhari and Muslim.)