Things which render the Salaah Makrooh

Looking around in Salaah

Q: If a person looks around in Salaah, what will be the position of his Salaah, will it be makrooh or will it break? Kindly explain the different situations i.e. if he only turned his face to the right or left during Salaah, or he turned his chest as well, or he only looked from the corner of his eye. Will there be any difference in the ruling of the above situations if there was a need for him to look?