Muwatta Malik · 431
Mauquf Sahih · Salim al-Hilali
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ أَبَا بَكْرٍ، وَعُمَرَ، كَانَا يَفْعَلاَنِ ذَلِكَ .
Yahya related to me from Malik that he had heard that Abu Bakr and Umar used to do that