The Sahabah (may Allah be pleased with them) were keen to learn how the Messenger of Allah (blessings and peace of Allah be upon him) prayed, then they were keen to teach this to the Muslims who came after them. In this hadith, Malik ibn al-Huwayrith (may Allah be pleased with him) – who used to watch the Prophet (blessings and peace of Allah be upon him) when he prayed, so that he could learn how he prayed and teach it to those who came after him – tells us that in the odd-numbered rak‘ahs of his prayer – meaning the first and third rak‘ahs – the Prophet (blessings and peace of Allah be upon him) did not get up to start the following rak‘ah straight after prostrating in these odd-numbered rak‘ahs. Rather he would sit briefly, which is called jalsat al-istirahah (the sitting of rest). It was said that this sitting is the completion of the rak‘ah, and it was said that the Prophet (blessings and peace of Allah be upon him) did that for a reason, either because of old age or sickness. And it was said that it is in fact part of the prayer, but it should be brief. This hadith indicates that jalsat al-istirahah (the sitting of rest) is permissible..