Yahya related to me from Malik from Sumayy, the mawla of Abu
Bakr, from Abu Salih as Samman, from Abu Hurayra that the Messenger of
Allah, may Allah bless him and grant him peace, said, "When the imam
has said, 'not of those with whom You are angry nor of those who are
in error,' say 'Amin', for the previous wrong actions of the one whose
utterance coincides with that of the angels, are forgiven him."
Muwatta Malik Book 3, Hadith 48
"The Messenger of Allah used to say: 'Allahumma inni a'udhu bika min 'adhabil-qabri, wa fitnatin-nar, wa fitnatil-qabr, wa 'adhabil-qabr, wa sharri fitnati masihid-dajjali wa sharri fitnatil-ghana', wa sharri fitnatil-faqri. Allahummaghsil khatayaya kama naqqaitath-thawbal-abyada minad-danas. Allahumma inni a'udhu bika minal-kasali walharami wal-maghrami wal-ma'tham (O Allah, I seek refuge with You from the torment of the grave, the tribulation of the Fire, the tribulation of the grave and the torment of the grave, the evil of the tribulation of Masihid-Dajjal, the evil of the tribulation of richness and the evil of the tribulation of poverty. O Allah, wash away my sins with water of snow and hail, and cleanse my heart of sin as a white garment is cleansed of filth. O Allah, I seek refuge with You from laziness, old age, debt and sin.)'"
Sunan an-Nasa'i Book 50, Hadith 50
"When we sat during the prayer with the Messenger of Allah (ﷺ), we used to say: 'Peace (salam) be upon Allah(SWT), peace be upon so-and-so and so-and-so.' The Messenger of Allah (ﷺ) said: 'Do not say peace (salam) be upon Allah (SWT), for Allah (SWT) is As-Salam (the Source of peace; the One free from all faults). Rather say: At-tahiyyatu lillahi wasalawatu wat-tayibaat, as-salamu 'alaika ayah-Nabiyyu wa rahmatAllahi wa baraktuhu. As-salamu 'alaina a 'ala ibad illahis-salihin (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.) If you say that, it will be for every righteous slave in the heavens and on earth, "ashadu an la ilaha ill Allah, wa ashhadu anna Muhammadan 'abduhu wa rasuluhu (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.) Then let him choose any supplication that he likes to say after that.'"
Sunan an-Nasa'i Book 13, Hadith 120