Hadith 3594
Narrated Abu Hurairah: The Prophet ﷺ said: Conciliation between Muslims is permissible. The narrator Ahmad added in his version: "except the conciliation which makes lawful unlawful and unlawful lawful. " Sulayman ibn Dawud added: The Messenger of Allah ﷺ said: Muslims are on (i. e. stick to) their conditions.
Hadith 4918
Narrated Abu Hurairah: The Prophet ﷺ said: The believer is the believer's mirror, and the believer is the believer's brother who guards him against loss and protects him when he is absent.
Hadith 5173
Narrated Abu Hurairah: The Prophet ﷺ said: When one has a look into the house, then there is no (need of) permission.