It was narrated from Hittan bin 'Abdullah that Al-Ash'ari said:

"The Messenger of Allah ﷺ addressed us and taught us our Sunnahs and our prayer. He said: 'When you stand for the prayer, make your rows straight, then let one of you lead the others. When he says the takbir, then say the takbir; when he says : "Wa lad-dallin" then say "Amin" and Allah (Subhanahu-wa-Taala) will answer you. Then when he says the takbir and bows, then say the takbir and bow, for the Imam bows before you and stands up before you.' The Prophet of Allah ﷺ said: "This makes up for that. When he says: 'Sami' Allahu liman hamidah (Allah hears the one who praises Him),' say: 'Allahumma, Rabbana wa lakal-hamd (O Allah, our Lord, to You be praise),' Allah will hear you, for indeed Allah (Subhanahu-wa-Taala), the Mighty and Sublime, has said on the tongue of His Prophet: "Allah hears the one who praises Him." Then when he says the takbir and prostrates, say the takbir and prostrate, for the Imam prostrates before you and rises before you.' The Prophet of Allah ﷺ said: 'This makes up for that. Then when you are sitting, let the following be among what one of you says: At-tahiyyatu lillahi wasalawatu wat-tayibaat, as-salamu 'alaika ayah-Nabiyyu wa rahmatAllahi wa baraktuhu. As-salamu 'alaina a 'ala ibad illahis-salihin, ashadu an la ilaha ill Allah, wa ashhadu anna Muhammadan 'abduhu wa rasuluhu. (All compliments, prayers and pure words are due to Allah. Peace be upon you O Prophet, and the mercy of Allah and His blessings. Peace be upon us and upon the righteous slaves of Allah. I bear witness that that none has the right to be worshipped except Allah, and I bear witness that Muhammad is His slave and messenger.)"

أَخْبَرَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ هِشَامٍ، عَنْ قَتَادَةَ، ح وَأَنْبَأَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا هِشَامٌ، قَالَ حَدَّثَنَا قَتَادَةُ، عَنْ يُونُسَ بْنِ جُبَيْرٍ، عَنْ حِطَّانَ بْنِ عَبْدِ اللَّهِ، أَنَّ الأَشْعَرِيَّ، قَالَ إِنَّ رَسُولَ اللَّهِ ﷺ خَطَبَنَا فَعَلَّمَنَا سُنَّتَنَا وَبَيَّنَ لَنَا صَلاَتَنَا فَقَالَ " إِذَا قُمْتُمْ إِلَى الصَّلاَةِ فَأَقِيمُوا صُفُوفَكُمْ ثُمَّ لْيَؤُمَّكُمْ أَحَدُكُمْ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا قَالَ { وَلاَ الضَّالِّينَ } فَقُولُوا آمِينَ يُجِبْكُمُ اللَّهُ ثُمَّ إِذَا كَبَّرَ وَرَكَعَ فَكَبِّرُوا وَارْكَعُوا فَإِنَّ الإِمَامَ يَرْكَعُ قَبْلَكُمْ وَيَرْفَعُ قَبْلَكُمْ " . قَالَ نَبِيُّ اللَّهِ ﷺ " فَتِلْكَ بِتِلْكَ وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا اللَّهُمَّ رَبَّنَا لَكَ الْحَمْدُ فَإِنَّ اللَّهَ عَزَّ وَجَلَّ قَالَ عَلَى لِسَانِ نَبِيِّهِ ﷺ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ ثُمَّ إِذَا كَبَّرَ وَسَجَدَ فَكَبِّرُوا وَاسْجُدُوا فَإِنَّ الإِمَامَ يَسْجُدُ قَبْلَكُمْ وَيَرْفَعُ قَبْلَكُمْ " . قَالَ نَبِيُّ اللَّهِ ﷺ " فَتِلْكَ بِتِلْكَ وَإِذَا كَانَ عِنْدَ الْقَعْدَةِ فَلْيَكُنْ مِنْ قَوْلِ أَحَدِكُمْ أَنْ يَقُولَ التَّحِيَّاتُ الطَّيِّبَاتُ الصَّلَوَاتُ لِلَّهِ السَّلاَمُ عَلَيْكَ أَيُّهَا النَّبِيُّ وَرَحْمَةُ اللَّهِ وَبَرَكَاتُهُ السَّلاَمُ عَلَيْنَا وَعَلَى عِبَادِ اللَّهِ الصَّالِحِينَ أَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَشْهَدُ أَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ " .