question #1 Sahih al-Bukhari 1130, Book 19, Hadith 10 : What does the Prophet’s dedication to prayer teach about gratitude in Islam?

The Prophet (ﷺ) used to stand (in the prayer) or pray till both his feet or legs swelled. He was asked why
(he offered such an unbearable prayer) and he said, “should I not be a thankful slave.”