Prayer is the mainstay of religion, and its performance is obligatory for every Muslim. The Prophet (may Allah's peace and blessings be upon him) demonstrated the manner of performing prayer and taught it to the Ummah. In this Hadīth, ‘Abdullāh ibn ‘Amr (may Allah be pleased with him) relates that it was narrated to him that the Prophet (may Allah's peace and blessings be upon him) stated that the prayer of a man while sitting is "half a prayer" i.e., it brings half of the reward of someone who performs it while standing. So, this makes it valid and detracts from its reward. This Hadīth is taken to refer to performing a supererogatory prayer while sitting despite being able to stand. However, if a person performs a supererogatory prayer while sitting because he is unable to stand, his reward does not decrease; rather, his reward is like praying while standing. As for the obligatory prayer, it is invalid to perform it while sitting despite being able to stand. Yet, if a person is unable to stand, then his sitting is tantamount to his standing. Then, ‘Abdullāh ibn ‘Amr (may Allah be pleased with him) informed that he came to the Prophet (may Allah's peace and blessings be upon him) one day and found him praying while sitting. He placed his hand on the Prophet's head, wondering at his prayer while sitting and wanting the Prophet (may Allah's peace and blessings be upon him) to look towards him. This was after he (may Allah's peace and blessings be upon him) had finished the prayer, for it is not thought that ‘Abdullāh ibn ‘Amr (may Allah be pleased with him) would put his hand before that. This behavior is not deemed impolite among some Arabs, as they tend to behave naturally. Moreover, this shows the Prophet's modesty and good character, and that he used to deal and associate with his close Companions like being one of them and not exalting himself above them. When the Prophet (may Allah's peace and blessings be upon him) sensed the hand of ‘Abdullāh, he asked him: "What is the matter with you?" i.e., what is wrong with you?! So, he told him about the aforementioned Hadīth, by way of inquiry, not as an objection or disapproval. His words "and you pray while sitting" affirmed the point that was confusing and unclear to him, and how the Prophet (may Allah's peace and blessings be upon him) would be content with half a reward for himself. In response, the Prophet (may Allah's peace and blessings be upon him) confirmed the Hadīth he cited and then said: "but I am not like any of you" i.e., what you have mentioned that the prayer of a man while sitting is half of his prayer while standing is a ruling that applies to people other than me in this Ummah and it pertains to them; as for me, I am not subject to this ruling, and my Lord accepts from me my prayer while sitting for a reward like that of my prayer while standing. This is one of the peculiar merits of the Prophet (may Allah's peace and blessings be upon him), as his performance of a supererogatory prayer while sitting, though he was able to stand, was made equivalent to his performance of it while standing, as an honor for him. The Hadīth urges the performance of prayer in its complete form for those who are able to. So, if a person is able to stand, he should pray while standing, in both obligatory and supererogatory prayers. It points out how Allah Almighty favors His Prophet (may Allah's peace and blessings be upon him) and distinguishes him from all the Ummah..