The ruling on prayer that lacks complete khushu'

You also say: Is it true that the prayer in which there is not complete khushu' for Allah (Mighty and Majestic) is not accepted from us, or is it not?
Answer: In any case, this is in danger, and what is required of the one praying is that he be humble in his prayer and devote himself to it; because Allah said: [Al-Mu'minun: 1-2], so devoting oneself to the prayer and being humble in it is among the most important matters, and it is its spirit. One should take care of khushu' and tranquility in the prayer, in his prostration, in his bowing, between the two prostrations, and after bowing when he straightens up; he should be humble and tranquil and not rush, whether he is a man or a woman, both of them. And if he neglects the khushu' in a way that involves pecking at the prayer and lacking tranquility, the prayer is invalid. But if he is tranquil in it, but some distracting thoughts or some forgetfulness may overtake him, this does not invalidate the prayer, but he has from his prayer only what he understood of it, and what he was humble in and devoted himself to; he will have the reward of that, and the reward of what he neglected will be lost to him. The servant should devote himself to the prayer, and be tranquil in it and humble in it for Allah (peace and blessings be upon him), so that his reward is completed. But it is not invalidated except if he neglects the tranquility. If he bows in a bowing that has no tranquility, rushing before the limbs become humble, and the obligatory thing is to be tranquil until every vertebra returns to its place, until he is able to say: (Subhan Rabbi al-Azim) in the bowing, until he is able to say: Subhan Rabbi al-A'la, until he is able to say: (Rabbana wa laka al-hamd) when he straightens up after rising from the bowing, and until he is able between the two prostrations to say: Rabbighfir li, he is tranquil. This is necessary. And when the Prophet (peace and blessings be upon him) saw a man who did not become tranquil in his prayer but rather pecked at it, he ordered him to repeat it, and he said to him: , so tranquility is among the most important of khushu', and it is an obligatory khushu' in the prayer, in the bowing and prostration, between the two prostrations, and in the state of straightening up from the bowing. This is called: it is named tranquility, and it is named khushu'. This tranquility is necessary, until every vertebra returns to its place. If he bows, he becomes tranquil until the bones return to their places, and every vertebra returns to its place. And when he rises, he becomes tranquil while standing after the bowing. And likewise when he prostrates, he becomes tranquil, until every vertebra returns to its place. And likewise between the two prostrations, he becomes tranquil and calm, and does not rush until every vertebra returns to its place. Yes.