The Prophet (ﷺ) used to say the Maghrib prayer immediately after the sun had set when its upper side would disappear.
Sunan Abi Dawud Book 2, Hadith 27
← Previous Hadith We used to offer the Maghrib prayer with the Prophet (ﷺ) and then shoot arrows, one of us could see the place where arrow would fall.

Sunan Abi Dawud Book 2, Hadith 26 Next Hadith → Marthad ibn Abdullah said: When AbuAyyub came upon us to fight the infidels and in those days Uqbah ibn Amir was the Governor of Egypt, he (Uqbah) delayed the sunset prayer. Hence AbuAyyub stood and said: What kind of prayer is this, Uqbah? He said: We were busy. He said: Did you not hear the Messenger of Allah (ﷺ) say: My community will remain well, or he said: will remain on its natural condition, so long as it would not delay the evening prayer until the stars shine brightly just like a network.

Sunan Abi Dawud Book 2, Hadith 28