What is the ruling on deliberate movement in prayer? And what is the minimum and maximum amount of it?

The Shaykh : What is the ruling on deliberate movement in prayer? And what is its minimum and maximum? Deliberate movement in prayer—oh daughter of Hala... later...—deliberate movement is either done out of the need of the one praying for it, in which case there is no harm in it. For example, if one swats a fly or scratches an itch, this is deliberate movement and there is no harm in it. However, if it is of the nature of playing around, then it is forbidden and not permissible. This is based on the saying of the Prophet (peace and blessings be upon him): , . As for numerous or few movements, regarding those that invalidate the prayer and those that do not, there is much disagreement among the jurists. The relied-upon position in the past among the Hanafi scholars—and this is the correct one—is that the movements which invalidate the prayer are those that, if a person looking at the one making them saw them, it would be predominant in his mind that he is not in prayer. This type of movement invalidates the prayer of the one making it. However, if the movements, whether few or many, do not suggest to the observer that he is not praying, then there is no harm in them. We mentioned in a recent or somewhat distant lesson what Imam al-Bukhari narrated in his Sahih: "That the Messenger (peace and blessings be upon him) entered into prayer one day with Umamah, the daughter of Zaynab, the daughter of the Messenger of Allah (peace and blessings be upon him), on his shoulders. When he bowed, he took her and placed her on the ground and prostrated. When he stood up for the second rak'ah, he took her from the ground and placed her on his shoulder, while he was leading the people in prayer as imam." He was not alone, and it was not a voluntary prayer, but an obligatory one, and he was the imam, and so on until the Messenger of Allah (peace and blessings be upon him) completed the prayer. The one looking at these movements, with the Messenger of Allah (peace and blessings be upon him) standing before Allah (Mighty and Majestic) with all humility, would not be predominant in his mind that he is not in prayer. And yet, he sees this girl on his shoulder (peace and blessings be upon him). Similarly, when he "prayed one day and prostrated in a prostration that he lengthened in the middle of his prayer, until it occurred to one of his Companions that the Messenger of Allah (peace and blessings be upon him) had perhaps died while prostrating." And it is not customary to prostrate this long prostration, "until one of them raised his head and looked like this, and he saw the Messenger of Allah (peace and blessings be upon him) with al-Hasan or al-Husayn on his back." So he understood that the reason for lengthening the prostration was for the sake of al-Hasan or al-Husayn . When he was reassured, he returned to the prostration as it was. When the Messenger of Allah (peace and blessings be upon him) finished his prayer and said the taslim, they said to him: "O Messenger of Allah, we saw you prostrated a prostration in the middle of your prayer that you did not used to prostrate?" He said (peace and blessings be upon him): إن ابني هذا - يشير إلى الحسن أو الحسين - كان قد ارتَحَلَني Indeed, this son of mine—he pointed to al-Hasan or al-Husayn—had climbed onto my back; meaning: the son of his daughter, and he lowered him from his back against his will, not because if he held him like that and lowered him, he would have made movements that invalidated his prayer, but because he did not want to disturb him. He did not want to carry him forcibly from his back to the ground so as not to disturb him. He said (peace and blessings be upon him): إنَّ ابني هذا كان قد ارتَحَلَني ، فكرهت أن أعجله Indeed, this son of mine had climbed onto my back, so I disliked to hasten him. And in Sahih al-Bukhari as well: "That a man from the Companions, in one of the expeditions, stood to pray while holding the reins of his horse in his hand." A man from the Tabi'un observed this man, not knowing that the one doing this was a noble Companion. He said: "I do not think he is anything but a senile man or a deaf one"; meaning, he did not know what he was doing, whether he was praying or not. "And the man heard what was being said about him. So after the prayer, he said to them—meaning: there is no senility in me, nor any loss of the prayer. And I have witnessed with the Messenger of Allah (peace and blessings be upon him) such and such expeditions. But I was afraid for my horse that it would get lost and run away." So he walked, meaning he took many, very many steps while still in prayer.
The point is: movements, however many they are, first: if they are for a need, there is absolutely no harm in them. Second: if they are many but it does not appear that he is not in prayer, then the prayer is valid. And in any case, the religion of Allah is ease, and whoever opposes this religion will be overcome by it.