عَنْ أَبِي هُرَيْرَةَ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ خَرَجَ إِلَى الصَّلَاةِ فَلَمَّا كَبَّرَ انْصَرَفَ وَأَوْمَأَ إِلَيْهِمْ أَنْ كَمَا كُنْتُمْ. ثُمَّ خَرَجَ فَاغْتَسَلَ ثُمَّ جَاءَ وَرَأَسُهُ يَقْطُرُ فَصَلَّى بِهِمْ. فَلَمَّا صَلَّى قَالَ: «إِنِّي كُنْتُ جُنُبًا فنسيت أَن أَغْتَسِل» . رَوَاهُ أَحْمد وروى مَالك عَن عَطاء بن يسَار نَحوه مُرْسلا

Nafi' said that ‘Abdallah b. ‘Umar passed a man while he was praying and gave him a salutation to which the man uttered some words in reply. ‘Abdallah b. ‘Umar went back to him and said to him, “When one of you is greeted while he is engaged in prayer he must not speak, but give a sign with his hand.” Malik transmitted it.