Abu Hurairah repons that the Prophet sallallahu alehi wasallam said: “When the call to prayer is made, the Satan takes to his heels… and when it is finished, he returns. He flees again when the iqamah is made and when it is finished, he returns until he comes between the man and his thoughts, saying: ‘Remember this and remember that,’ which he had not recalled, until the person does not know how much he has prayed, [i.e.,] three or four rak’at. Then, he makes two prostrations while sitting.” This is reported by al-Bukhari and Muslim.
Al-Bukhari also records that ‘Umar said: “I arrange the troops [in my mind] during the salah.” Although it is true that such a salah is valid and sufficient, it is a must for the person in prayer to keep his mind and heart attuned to the salah and his Lord and to keep his thoughts on the meaning of the Qur’anic verses and the significance of the different acts of the salah since a person has for him only that portion of the salah which he is fully aware of [while performing it].
Au Dawud, an-Nasa’i, and Ibn Hibban record from ‘Ammar ibn Yasir that he heard the Messenger of Allah say: “A man may complete the salah and only have recorded for himself one-tenth or one-ninth or one-eighth or one-seventh or one-fifth or one-fourth or one third or one-half.”
Al-Bazzar records from Ibn ‘Abbas that the Messenger of Allah said: “Allah, the Glorious, said: ‘I accept the salah of one who humbles himself during it to My Greatness; and who does not perform the salah just for show; and who does not spend the night in disobedience to Me; and who spends the day remembering Me; and who is merciful to the poor, the wayfarer and the widows; and who is merciful to one who is suffering from an infliction. He has a light like the light of the sun. I protect him by My Glory and the angels guard over him. I give him light in darkness and sobriety in the presence of ignorance. And his similitude in My creation is like al-Firdaus in Paradise.”‘
Abu Dawud records from Zaid ibn Khalid that the Messenger of Allah said: “Whoever makes ablution and perfects it and then prays two rak’at, without being unheedful during them, forgiven for him will be his previous sins.” Muslim records that ‘Uthman ibn Abi al-‘Aas said: “O Messenger of Allah, the Satan comes between me and my prayers and my recitation, confusing me therein!” The Prophet said: “That Satan is called Khanzab. If he affects you seek refuge in Allah from him and ‘spit out’ on your left side three times.”
Muslim records from Abu Hurairah that the Messenger of Allah said: “Allah, the Glorious, said: ‘I have divided the salah [i.e., al-Fatihah] into two halves, between Me and My slave, and my slave shall receive what he asks for.’ When the slave says ‘All praise is due to Allah, the Lord of the Worlds,’ Allah, the Exalted, says ‘My slave has praised Me.’ When he says ‘The Compassionate, the Merciful,’ Allah, the Exalted, says ‘My slave has lauded Me.’ When he says ‘Master of the Day of Judgment.’ Allah, the Exalted says ‘My servant has glorified Me and entrusted his affairs to Me.’ And when he says ‘It is Thee we worship and from Thee that we seek aid,’ Allah, the Exalted, says ‘This is between Me and My slave. And for My slave is what he asks.’ And when he says ‘Guide us to the straight path, the path of those whom you have blessed and not of those with whom you are angry nor of those who have gone astray.’ Allah says ‘That is for My slave and My slave shall get what he asks for.'”
It is disliked for anyone to leave any of the sunnah acts described earlier.