I went along with Shurahbil b. al-Simt to a village which was situated at a distance of seventeen or eighteen miles, and he said only two rak'ahs of prayer. I said to him (about it) and he said: I saw 'Umar observing two rak'ahs at Dhu'l-Hulaifa and I (too) said to him (about it) and he said: I am doing the same as I saw the Messenger of Allah ﷺ doing.  

رَأَيْتُ عُمَرَ صَلَّى بِذِي الْحُلَيْفَةِ رَكْعَتَيْنِ فَقُلْتُ لَهُ فَقَالَ إِنَّمَا أَفْعَلُ كَمَا رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَفْعَلُ  

I saw 'Umar bin al-Khattab in Dhul­-Hulaifah praying two rak'ahs and I asked him (about that). He said: I am only doing what I saw the Messenger of Allah ﷺ do.  

يُقَالُ لَهَا دَوْمِينُ مِنْ حِمْصَ عَلَى رَأْسِ ثَمَانِيَةَ عَشَرَ مِيلًا فَصَلَّى رَكْعَتَيْنِ فَقُلْتُ لَهُ أَتُصَلِّي رَكْعَتَيْنِ؟ فَقَالَ رَأَيْتُ عُمَرَ بْنَ الْخَطَّابِ بِذِي الْحُلَيْفَةِ يُصَلِّي رَكْعَتَيْنِ فَسَأَلْتُهُ فَقَالَ إِنَّمَا أَفْعَلُ كَمَا رَأَيْتُ رَسُولَ اللهِ ﷺ أَوْ قَالَ فَعَلَ رَسُولُ اللهِ ﷺ