Hadith
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، وَعُثْمَانَ بْنَ عَفَّانَ، - رضى الله عنهما - كَانَا يَفْعَلاَنِ ذَلِكَ .
Yahya related to me from Malik from Ibn Shihab from Said ihn al-Musayyab that Umar ibn al Khattab and Uthman ibn Affan, may Allah be pleased with them, used to do the same
Sahih · Salim al-Hilali
Muwatta Malik 419 ·Book 9, Hadith 94·Also available on sunnah.com·