Sahih Muslim Book 32, Hadith Number 6211.

Chapter : It is forbidden for a Muslim to have estranged relations with the other Muslim beyond three days without any reason of Shari’ah.

This hadith has been transmitted on the authority of Zuhri with a slight variation of wording (and the words are): “The one turning away and the other turning away when they meet and one avoids the other and the other also avoids him.”