ENOfficial
Anas ibn Malik reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "Do not hate one another nor envy one another nor shun one another. Slaves of Allah, be brothers! It is not lawful for a Muslim to refuse to speak to his brother (Muslim) for more than three nights."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا إِسْمَاعِيلُ قَالَ: حَدَّثَنِي مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّ رَسُولَ اللهِ صلى الله عليه وسلم قَالَ: لاَ تَبَاغَضُوا، وَلاَ تَحَاسَدُوا، وَلاَ تَدَابَرُوا، وَكُونُوا عِبَادَ اللهِ إِخْوَانًا، وَلاَ يَحِلُّ لِمُسْلِمٍ أَنْ يَهْجُرَ أَخَاهُ فَوْقَ ثَلاَثِ لَيَالٍ.
sunnah.com