Abu Musa asked permission to enter upon ʿUmar, but seeing that he was busy, he went away. ʿUmar then said, "Didn't I hear the voice of ʿAbdullah bin Qais? Allow him to come in." He was called in and ʿUmar said to him, "What made you do what you did." He replied, "We have been instructed thus by the Prophet" ʿUmar said, "Bring proof (witness) for this, other wise I will do so-and-so to you." Then ʿAbdullah bin Qais went to a gathering of the Ansar who then said, "None but the youngest of us will give the witness for it." So Abu Saʿid Al-Khudri got up and said, "We used to be instructed thus (by the Prophet)." ʿUmar said, "This tradition of the Prophet ﷺ remained hidden from me. Business in the market kept me busy."  

فَأْتِنِي عَلَى هَذَا بِبَيِّنَةٍ أَوْ لأَفْعَلَنَّ بِكَ فَانْطَلَقَ إِلَى مَجْلِسٍ مِنَ الأَنْصَارِ فَقَالُوا لاَ يَشْهَدُ إِلاَّ أَصَاغِرُنَا فَقَامَ أَبُو سَعِيدٍ الْخُدْرِيُّ فَقَالَ قَدْ كُنَّا نُؤْمَرُ بِهَذَا فَقَالَ عُمَرُ خَفِيَ عَلَىَّ هَذَا مِنْ أَمْرِ النَّبِيِّ ﷺ أَلْهَانِي الصَّفْقُ بِالأَسْوَاقِ