Allah's Messenger said: "Whoever says, when he hears the Mu'adh-dhin: (Wa Ana Ashadu An La Ilaha Illallah, Wahdahu La Sharika Lahu, Wa Anna Muhammadan Abduhu Wa Rasuluhu, Radittu Billahi Rabban Wa Bil-Islam Dinan, Wa Bi Muhammadin Rasulan) 'I too testify that none has the right to be worshiped but Allah, Alone without partners, and that Muhammad is His slave and Messenger, I am pleased with Allah as my Lord, with Islam as my religion and Muhammad as a Messenger.' - Allah will pardon his sins for him."
Jami` at-Tirmidhi Book 2, Hadith 62
"When these Ayat were revealed to the Prophet (ﷺ): 'Allah only wishes to remove the Rijs from you, O members of the family, and to purify you with a thorough purification (33:33)' in the home of Umm Salamah, he called for Fatimah, Hasan, Husain, and wrapped him in the cloak, and 'Ali was behind him, so he wrapped him in the cloak, then he said: 'O Allah! These are the people of my house, so remove the Rijs from them, and purify them with a thorough purification.' So Umm Salamah said: 'And I, Prophet of Allah?' He said: 'You are in your place (meaning you are already a member of my household), and you are goodness.'"
Jami` at-Tirmidhi Book 47, Hadith 257
Yahya related to me from Malik that he had heard that Ali ibn Abi
Talib said about the two arbiters about whom Allah, the Exalted,
said,"If you fear a breach between the two, appoint an arbiter from
his people, and an arbiter from her people. If they desire to set
things aright, Allah will make peace between them, surely Allah is
Knowing, Aware," (Sura 4 ayat 35), that the separation and the joining
were overseen by the two of them.
Malik said, "That is the
best of what I have heard from the people of knowledge. Whatever the
two arbiters say concerning separation or joining is taken into
consideration "
Muwatta Malik Book 29, Hadith 79