Abu Ja’far (Imam Baqir) (a.s.) said:“When you stand up for prayer, you should be prepared for it; what is counted of prayer in your favor is only the part where you were attentive; you should not play with your hands, head and beard during prayer, and you should not speak to yourself. You should not yawn, stretch out your hands or fold one over the other; that is what the Zoroastrians (Majus) do. You shall not cover your face, you shall not feel the urge (to urinate); you shall not keep your feet far apart as camels do, you shall not sit on your heels, you shall not lay your arms flat on the ground, you shall not crack your fingers; each of these things causes a lack in prayer.You should not stand in a state of laziness, snooze or feel burdened; each of these things is from the behaviour of the hypocrites.Allah, the Exalted, has forbidden the believers to stand in a state of laziness in prayer, that is, to feel tired. He said of the hypocrites: “And when they stand up for prayer, they stand lazily, wanting to be seen by men, and remember Allah very little. (4:142)“ [Al-Kafi, Volume 3, Page 299]

قال أبو جعفر (عليه السلام): إذا قمت في الصلاة فعليك بالاقبال على صلاتك فإنما يحسب لك منها ما أقبلت عليه ولا تعبث فيها بيدك ولا برأسك ولا بلحيتك ولا تحدث نفسك ولا تتثاءب ولا تتمط ولا تكفر (2) فإنما يفعل ذلك المجوس ولا تلثم ولا تحتفز [ولا] تفرج كما يتفرج البعير ولا تقع على قدميك ولا تفترش ذراعيك ولا تفرقع أصابعك فإن ذلك كله نقصان من الصلاة ولا تقم إلى الصلاة متكاسلا ولا متناعسا ولا متثاقلا فإنها من خلال النفاق فإن الله سبحانه نهى المؤمنين أن يقوموا إلى الصلاة وهم سكارى يعنى سكر النوم وقال للمنافقين: “ وإذا قاموا إلى الصلاة قاموا كسالى يراؤن الناس ولا يذكرون الله إلا قليلا