Abu Abdillah al Sadiq (as) said : When you stand in your Salat, be fearful in it and do not think [of other things] if you are able to do so, and humble your neck and do not turn around in it, and your sight should not exceed the place of your prostration, and row your feet and affirm them, and let down your hands, and do not fold your hands, nor lean on one leg at times, and on the other at times.
Divine Treasure 