Is it permissible to utilize breathing and focus exercises derived from Yoga and Indian meditation, after stripping them of their false beliefs and rituals, to achieve devotion (khushūʿ), tranquility, and relaxation during prayer (ṣalāt) and Quran recitation, or during moments of stillness in bowing (rukūʿ) and prostration (sujūd), or by focusing on the feeling of calmness and serenity?

Prayer is a great act of worship. The Prophet, peace and blessings be upon him, commanded us to pray as the Companions saw him pray. It was narrated that he said: "Indeed, there is preoccupation in prayer," because it is a communion with Allah Almighty, so it is not permissible to be preoccupied with anything else during it.

Being preoccupied with breathing exercises, concentration techniques, and relaxation methods during prayer contradicts its meaning. The Sunnah in prayer is to be preoccupied with the meanings of the prescribed remembrances, such as recitation, takbeer (saying "Allahu Akbar"), tasbeeh (saying "Subhan Allah"), and supplication, and to be absorbed in the implications of its prescribed postures, such as standing, bowing, prostrating, and sitting, while being mindful of Allah Almighty and striving to reach the level of Ihsan (excellence in worship).

Benefiting from prayer is not achieved through these aforementioned methods, but rather through beneficial knowledge and righteous deeds, and by striving to learn how to pray and attain humility in it through the texts of revelation and the words of scholars, then by striving against one's self to implement what has been learned. As for these methods, there is ample room for their use outside of prayer.