What is the ruling on praying without a satr (garment that covers the body), and what is the wisdom behind it? Is al-Isbal (letting one's garment hang below the ankles) a condition for the validity of prayer?

Most jurists hold that covering the awrah (intimate parts) is a condition for the validity of prayer. For a man, the awrah is from the navel to the knee. For a free woman, it is her entire body except for the face and the palms of the hands. Prayer is valid even if performed in a single garment that covers the awrah, but it is recommended to adorn oneself by wearing two or more garments if possible. As for not wearing an abaya during prayer, it does not affect its validity, though it is recommended if it is customary for the women of the land to adorn themselves with it. Regarding the lengthening of garments (isbal), it is not permissible for a man to lengthen his shirt, izar (lower garment), or trousers, even if not done out of arrogance. However, for a woman, isbal is permissible.