When he was silent from raising his voice in speech, the Prophet, peace and blessings be upon him, used to supplicate quietly during his silence between the first takbir and the recitation.

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that when the Prophet (peace and blessings be upon him) would say the (opening) takbeer in prayer, he would remain silent between the takbeer and the recitation. I said to him, "May my parents be sacrificed for you, tell me, what is your silence between the takbeer and the recitation?" The Prophet (peace and blessings be upon him) said: I recite this supplication «‏‏‏‏اللَّهُمَّ بَاعِدْ بَيْنِي وَبَيْنَ خَطَايَايَ كَمَا بَاعَدْتَ بَيْنَ الْمَشْرِقِ وَالْمَغْرِبِ، اللَّهُمَّ نَقِّنِي مِنْ خَطَايَايَ كَمَا يُنَقَّى الثَّوْبُ الأَبْيَضُ مِنْ الدَّنَسِ، اللَّهُمَّ اغْسِلْنِي مِنْ خَطَايَايَ بِالْمَاءِ وَالثَّلْجِ وَالْبَرَدِ» ‏‏‏‏ "O Allah, distance me from my sins as You have distanced the East from the West. O Allah, purify me of my sins as a white garment is purified of dirt. O Allah, wash away my sins with water, snow, and hail."

Sayyiduna Abu Qatadah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) used to prolong the first rak'ah of the Fajr and Dhuhr prayers. We used to think that he did this so that people could join (the prayer).

Sayyiduna Ubadah bin Samit (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) led us in the morning prayer, and recitation became heavy and difficult for him. Then, when he finished the prayer, he asked: "Surely, I think you recite behind your Imam?" They say, we replied, "Yes, by Allah, O Messenger of Allah (we recite quickly)." The Prophet (peace and blessings be upon him) said: "Then do not recite anything except Umm al-Kitab, because whoever does not recite Surah Al-Fatihah, his prayer is not valid." This hadith is from Ibn Ulayyah and Abdul A'la.

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him), while teaching us (about prayer), used to say: "When the imam says the takbir, you should also say the takbir, and when he recites «‏‏‏‏غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ» ‏‏‏‏, you should say Ameen."

When the imam says "Ameen," the believer hopes for forgiveness of his past sins if his saying "Ameen" coincides with that of the angels, with evidence that the imam is required to say "Ameen" aloud when he recites aloud, so that the follower may hear his "Ameen." For it is not permissible for the Prophet, peace and blessings be upon him, to command the follower to say "Ameen" when his imam says "Ameen," while there is no way for him to know the imam's "Ameen" if the imam conceals it.

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that I heard the Messenger of Allah (peace and blessings be upon him) say: "When the Imam says Ameen, you should also say Ameen. Thus, whoever's Ameen coincides with the Ameen of the angels, his previous sins are forgiven."

Hazrat Hattan bin Abdullah al-Raqashi narrates that Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) led us in prayer. Then when he finished the prayer, he said that indeed the Messenger of Allah (peace be upon him) delivered a sermon to us, explained to us our Sunnahs, and taught us our prayer. He (peace be upon him) said: "When the Imam says the takbeer, you also say the takbeer, and when he recites «‏‏‏‏غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ ‎» , you say Ameen. Allah Almighty will accept your supplication." Imam Abu Bakr (may Allah have mercy on him) says that this hadith relates to the follower saying Ameen after the Imam has finished reciting Surah Al-Fatihah, even if the Imam, due to ignorance or forgetfulness, does not say Ameen.

Lady Aisha (may Allah be pleased with her) narrates that a Jew came to the Prophet Muhammad (peace be upon him) and said: «‏‏‏‏السَّامُ عَلَيْكَ» ‏‏‏‏ "May death be upon you." The Prophet Muhammad (peace be upon him) replied to him: «‏‏‏‏وَعَلَيْكَ» ‏‏‏‏ "And may death be upon you too." Lady Aisha (may Allah be pleased with her) says that I intended to speak, but realizing the dislike of the Messenger (peace be upon him), I remained silent. Then another Jew came and he also said: «‏‏‏‏السَّامُ عَلَيْكَ» ‏‏‏‏ "May death befall you." The Prophet (peace be upon him) replied: «‏‏‏‏وَعَلَيْكَ» ‏‏‏‏ "And upon you too." Again, I intended to speak, but I realized the Messenger's (peace be upon him) dislike (so I remained silent). Then a third one came and he also said: «‏‏‏‏السَّامُ عَلَيْكَ» ‏‏‏‏ "May death befall you." This time I could not remain patient, so I replied: "And may death befall you too. May Allah's wrath and curse be upon the brothers of pigs and monkeys. Do you greet the Messenger of Allah in this manner, which Allah has not taught you to greet him with?" Then the Messenger of Allah (peace be upon him) said: "Surely Allah does not like foul language and indecency in speech or action. These Jews said something, so we replied to them in kind. Indeed, the Jews are a very jealous people, and they are not as jealous of anything of ours as they are of the way we greet each other and say 'Ameen'."

This characteristic was not granted to any prophet before you. It was only granted to Hazrat Harun (peace be upon him) when Hazrat Musa (peace be upon him) made supplication and Hazrat Harun (peace be upon him) said Ameen. Provided that the narration reported in this regard is authentic.