(193) بَابُ إِنَّ السّلامَ يُجْزِئُ مِنَ الصَّرْمِ
Abu Hurayra reported that he heard the Prophet, may Allah blesshim and grant him peace, say, "It is not lawful for a Muslim man to refuseto speak to a believer for more than three days. When three days have passed,he should meet him and greet him. If he returns the greeting, they sharein the reward. If he does not return the greeting, the one who gives thegreeting is innocent of having severed relations."
Reference: Al-Adab Al-Mufrad 414
In-book reference: Book 22, Hadith 18
English translation: Book 22, Hadith 414