Ṣaḥīḥ Muslim

Hittān ibn' Abdullāh ar-Raqāshi reported: I observed prayer with Abu Mūsa al-Ash'ari, and when he was in the tashahhud, someone among the people said: "The prayer has been made obligatory along with benevolence and Zakah." When Abu Mūsa finished the prayer and made taslīm, he turned to the people and said: "Who amongst you said such and such thing?" A hush fell on the people. He again said: "Who amongst you has said such and such thing?" A hush fell on the people.

He said, "O Hittān, perhaps you have uttered it." Hittān said: "No, I have not uttered it. I feared you might be annoyed with me because of this." A person amongst the people said: "It was I who said it, and I intended nothing but good with it." Abu Mūsa said: "Do you not know what you have to say in your prayers?

Verily, the Messenger of Allah (may Allah's peace and blessings be upon him) addressed us, explaining to us our Sunnah and teaching us our prayer, and said: 'When you pray, straighten your rows and let one of you lead in prayer, and when he says takbīr, say takbīr; when he recites {Not of those who incurred Your Wrath, or of those who went astray} [Surat al-Fātihah: 7], say 'amen'; and Allah will respond to you.

And when he says takbīr, you also say takbīr, for the Imām bows and rises before you.' Then, the Messenger of Allah (may Allah's peace and blessings be upon him) said: 'This is equivalent to that.

And when he says, 'Sami'a Allāhu liman hamidah' (Allah hears he who praises Him), you should say: 'Allahumma rabbanā laka al-hamd' (O Allah, our Lord, praise be to You), and Allah will hear you, for Allah Almighty said through the tongue of His Prophet (may Allah's peace and blessings be upon him): Allah hears he who praises Him.

And when he says takbīr and prostrates, you should also say takbīr and prostrate, for the Imām prostrates before you and rises before you.' Then, the Messenger of Allah (may Allah's peace and blessings be upon him) said: 'This is equivalent to that. And when he sits for tashahhud, the first words of everyone amongst you should be: 'Attaḥiyyāt at-ṭayyibāt aṣ-ṣalawātu lillāhi, assalāmu 'alayka 'ayyuh an-nabiyyu wa raḥmatullāhi wa barakātuh, assalāmu' alayna wa 'alā 'ibadillāhi aṣ-ṣāliḥīn.

Ash'hadu an lā 'ilāha illā Allah wa ash'hadu anna Muhammadan ‘abduhu wa rasūluh.' (All greetings, good things, and prayers are due to Allah. Peace be upon you, O Prophet, and Allah's mercy and blessings. Peace be upon us and the righteous servants of Allah. I testify that there is no god but Allah and that Muhammad is His servant and His Messenger)."