Language:
كتاب النكاح
67
Wedlock, Marriage (Nikaah)
(4)
Chapter: About (marrying) several women
(4)
باب كَثْرَةِ النِّسَاءِ

Narrated Sa`id bin Jubair:

Ibn `Abbas asked me, "Are you married?" I replied, "No." He said, "Marry, for the best person of this (Muslim) nation (i.e., Muhammad) of all other Muslims, had the largest number of wives."

حَدَّثَنَا عَلِيُّ بْنُ الْحَكَمِ الأَنْصَارِيُّ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ رَقَبَةَ، عَنْ طَلْحَةَ الْيَامِيِّ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، قَالَ قَالَ لِي ابْنُ عَبَّاسٍ هَلْ تَزَوَّجْتَ قُلْتُ لاَ‏.‏ قَالَ فَتَزَوَّجْ فَإِنَّ خَيْرَ هَذِهِ الأُمَّةِ أَكْثَرُهَا نِسَاءً‏.‏
Reference : Sahih al-Bukhari 5069
In-book reference : Book 67, Hadith 7
USC-MSA web (English) reference : Vol. 7, Book 62, Hadith 7
  (deprecated numbering scheme)