Abu Hurayra reported that he heard the Prophet, may Allah bless
him and grant him peace, say, "It is not lawful for a Muslim man to refuse
to 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 share
in the reward. If he does not return the greeting, the one who gives the
greeting is innocent of having severed relations."