What is the jurisprudence derived from this hadith: (I heard 'Umar while he was delivering a sermon and saying

The Shaykh : The second and final question on this sheet. It says: "Ahmad and al-Bayhaqi narrated from Siyar, who said: I heard 'Umar while he was delivering a sermon and saying: " This report from 'Umar ibn al-Khattab is addressed in the question: What is the jurisprudence extracted from this hadith? More than one issue is taken from this hadith: First: If the crowd in the mosque becomes so dense that when they prostrate, some rows do not find space to place their foreheads on the ground, what does the one who does not find space for prostration do? So 'Umar says: He prostrates on the back of his brother. And if we imagine this scene, it means: prostrate, and you are bowing, otherwise if you place your hands on the ground prostrating with your knees, you cannot reach your forehead to the back of the brother prostrating in front of you. But the reality is that you place your forehead on the lower part of his back. What does it mean if 'Umar says to prostrate on the back of his brother? It appears that you do not place your knees on the ground and you do not place your hands on the ground, but while bowing, you lower your head like this a little and place your forehead on the back of your brother. This is the opinion of 'Umar ibn al-Khattab. And there is another opinion, which is the one I prefer: if there is almost a crowd in the mosque such that a person cannot place his forehead on the ground, the action is for this one who did not find a place for prostration to be patient until the people raise their heads, and then you prostrate at that time. You must find space, even if it is between the feet. This opinion is dearer to me. Why? Because first, we have imagined that in 'Umar's opinion, one cannot prostrate on his back without placing the knees and hands, so the prostration would remain deficient by a great deficiency. That is because the Messenger—peace be upon him—mentioned in more than one hadith that the complete prostration is that in which the Muslim is able to place seven limbs on the ground, as he said—peace be upon him—: And in a narration: meaning: limbs. Then he—may Allah's prayers and peace be upon him—mentioned the two hands, the two knees, the tips of the toes of the two feet, and the forehead, and he passed his finger over his nose, meaning he indicated that they are one limb. So it is necessary to realize the obligatory prostration to prostrate on these seven limbs. According to what 'Umar held, a person cannot prostrate on seven limbs at all. So if there is another saying of some Muslim scholars in which a person can prostrate on seven limbs, that is dearer to us and closer to realizing the commanded prostration. And another thing, and the last, is that placing the forehead on the back of the one in front of him, according to the previous explanation, is like speaking in a way that is not pleasing in the Shari'ah. It has come in the authentic Sunnah, and I mentioned that in the beginning of my book "The Description of the Prayer of the Prophet (peace and blessings be upon him) from the Takbir to the Taslim as if you are seeing it": It is established in the Sunnah: "That the Messenger—peace be upon him—saw a sick man who could not place his forehead on the ground, so he was placing something like a pillow or similar to raise it from the ground, and he would place his forehead on that thing and prostrate on it. So the Messenger—peace be upon him—forbade him and ordered that sick man to prostrate as much as he is able, but to make his prostration lower than his bowing." So this man took an intermediary between his forehead and the ground by placing a stick, meaning a tree trunk, or for example a large mound or similar, thinking that this is closer to the Shari'ah. So the Messenger—peace be upon him—forbade him to take an intermediary connecting his forehead to the ground because it involves difficulty and excessive strictness. And he said—peace be upon him—: Let him prostrate as much as he is able, but let him make his prostration lower than his bowing. So this prohibition is similar to his placing his forehead on the back of the praying person. No. So here are two cases; we remember the other case that I forgot to mention earlier: If you cannot, even if the people raise their heads from prostration to standing, and you do not find a place for prostration, this is a very rare image. So it is sufficient that you indicate like this with your head, lower than your bowing, and Allah is sufficient for the believers in fighting. This is what is taken from the hadith regarding 'Umar's order to prostrate on the back of a man.