Musnad Ahmad 25:210

Asbat ibn Muhammad narrated to us, ‘Ata’ ibn al-Sa’ib narrated to us, from Sa’id ibn Jubayr, who said: Ibn Abbas met me and said: "Have you married?" I said: "No." He said: "Marry." Then he met me after that and said: "Have you married?" I said: "No." He said: "Marry, for the best of this nation was the one with the most wives."