Narrator:Anas ibn Mālik
حَدَّثَنَا يُوسُفُ بْنُ رَاشِدٍ، حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ سُفْيَانَ، حَدَّثَنَا أَيُّوبُ، وَخَالِدٌ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَنَسٍ، قَالَ مِنَ السُّنَّةِ إِذَا
تَزَوَّجَ الرَّجُلُ الْبِكْرَ عَلَى الثَّيِّبِ أَقَامَ عِنْدَهَا سَبْعًا وَقَسَمَ، وَإِذَا تَزَوَّجَ الثَّيِّبَ عَلَى الْبِكْرِ أَقَامَ عِنْدَهَا ثَلاَثًا ثُمَّ قَسَمَ
Anas (may Allah be pleased with him) was reported to have said: "It is a Sunnah for a man who marries a virgin when he already has a wife (who is no longer a virgin) that he stay seven nights with the new wife and then divide his overnight stay between both. If he marries a previously-married woman when he already has a wife (either a virgin or not), the Sunnah is for him to stay with her (the new wife) three nights and then divide his overnight stay between both." Abu Qilābah said: "If I wanted to do so, I could say that Anas attributed (this Hadīth) to the Prophet (may Allah's peace and blessings be upon him)."
Reported by Al-Bukhari (No. 5214, 5213), Muslim (No. 1461a), Abu Dawud (No. 2123, 2124) and At-Tirmidhi (No. 1139).