For this reason, it is narrated from one of the early righteous predecessors: “Whoever is not restrained by his prayer from indecency and wrongdoing, it only increases him in distance from Allah.” For if he prayed the prayer in its complete form, it would necessarily restrain him from indecency and wrongdoing, because Allah says:

“Establish prayer. Indeed, prayer restrains from indecency and wrongdoing.” [al-‘Ankabut 29:45]

This is a statement from Allah, emphasized by the word “indeed.”

So, if you pray a prayer and do not find your heart restrained from indecency and wrongdoing, then know that you have only performed a prayer by which you have merely discharged your obligation. How often do you see a person enter his prayer and leave it exactly as he was, finding no effect from it? Yet if Allah bestows His favor upon him one day, so that his heart is attentive, he is tranquil and unhurried, and he reflects upon what he says and does, then he leaves in a state different from that in which he entered. He finds an effect and a sweetness that he savors, even after some time has passed, as he remembers that prayer in which his heart was attentive and tranquil.

In short, tranquillity is indispensable; together with humility, it is in reality the soul of the prayer.

And the final tashahhud, ............

His statement, “And the final tashahhud”: this is the tenth pillar of the prayer.

The evidence for this is the hadith of Abdullah ibn Mas‘ud, may Allah be pleased with him, who said: “Before the tashahhud was made obligatory upon us, we used to say: ‘Peace be upon Allah from His servants; peace be upon Gabriel and Michael; peace be upon so-and-so and so-and-so.’” (1) The point of evidence in this hadith is his statement: “Before the tashahhud was made obligatory upon us.”