Sunan an-Nasa'i 591

It was narrated that Isma'il bin 'Abdur-Rahman, a Shaikh of the Quraish, said:"I accompanied Ibn 'Umar to Al-Hima. [1] When the sun set I felt too nervous to remind him of the prayer, so he went on until the light on the horizon had disappeared and it was getting dark, then he stopped and prayed Maghrib, three Rak'ahs, then he prayed two Rak'ahs immediately afterwards, then he said: 'This what I saw the Messenger of Allah (ﷺ) do.'" [1] A place near Madinah