Anas b. Malik reported: Messenger of Allah ﷺ came to our house and he asked for a drink. We milked a goat for him and then mixed it (the milk) with the water of this well of mine. I gave it to Messenger of Allah ﷺ and he drank it, while Abu Bakr was on his left and 'Umar was in front of him, and a desert Arab was on his right. When Messenger of Allah ﷺ had finished the drink, Umar said: Allah's Messenger, here is Abu Bakr, give him to drink;
but Messenger of Allah ﷺ gave it to the desert Arab and he left out Abu Bakr and Umar. And Messenger of Allah ﷺ said: Those on the right, those on the right, those on the right (deserve preference). Anas said: This is the Sunnah, this is the Sunnah, this is the Sunnah.

حَدَّثَنَا يَحْيَى بْنُ أَيُّوبَ، وَقُتَيْبَةُ، وَعَلِيُّ بْنُ حُجْرٍ، قَالُوا حَدَّثَنَا إِسْمَاعِيلُ، - وَهُوَ ابْنُ جَعْفَرٍ - عَنْ عَبْدِ اللَّهِ بْنِ عَبْدِ الرَّحْمَنِ بْنِ مَعْمَرِ بْنِ حَزْمٍ أَبِي طُوَالَةَ الأَنْصَارِيِّ، أَنَّهُ سَمِعَ أَنَسَ بْنَ مَالِكٍ، ح وَحَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ بْنِ قَعْنَبٍ، - وَاللَّفْظُ لَهُ - حَدَّثَنَا سُلَيْمَانُ، - يَعْنِي ابْنَ بِلاَلٍ - عَنْ عَبْدِ اللَّهِ بْنِ عَبْدِ الرَّحْمَنِ، أَنَّهُ سَمِعَ أَنَسَ بْنَ مَالِكٍ، يُحَدِّثُ قَالَ أَتَانَا رَسُولُ اللَّهِ ﷺ فِي دَارِنَا فَاسْتَسْقَى فَحَلَبْنَا لَهُ شَاةً ثُمَّ شُبْتُهُ مِنْ مَاءِ بِئْرِي هَذِهِ - قَالَ - فَأَعْطَيْتُ رَسُولَ اللَّهِ ﷺ فَشَرِبَ رَسُولُ اللَّهِ ﷺ وَأَبُو بَكْرٍ عَنْ يَسَارِهِ وَعُمَرُ وُجَاهَهُ وَأَعْرَابِيٌّ عَنْ يَمِينِهِ فَلَمَّا فَرَغَ رَسُولُ اللَّهِ ﷺ مِنْ شُرْبِهِ قَالَ عُمَرُ هَذَا أَبُو بَكْرٍ يَا رَسُولَ اللَّهِ . يُرِيهِ إِيَّاهُ فَأَعْطَى رَسُولُ اللَّهِ ﷺ الأَعْرَابِيَّ وَتَرَكَ أَبَا بَكْرٍ وَعُمَرَ وَقَالَ رَسُولُ اللَّهِ ﷺ " الأَيْمَنُونَ الأَيْمَنُونَ الأَيْمَنُونَ " . قَالَ أَنَسٌ فَهِيَ سُنَّةٌ فَهِيَ سُنَّةٌ فَهِيَ سُنَّةٌ .