Sunan Abi Dawud Book 5, Hadith 34
The Messenger of Allah (ﷺ) as saying: Between the two adhans there is a prayer, between the two adhans there is prayer for one who desires (to offer).
I offered two rak'ahs of prayer before the Maghrib prayer (i.e. obligatory) during the time of the Messenger of Allah (ﷺ). I (narrator al-Mukhtar b. Fulful) asked Anas: Did the Messenger of Allah (ﷺ) se you ? He replied: Yes, but he neither commanded us nor forbade us (to do so).
Ibn 'Umar was asked about praying two rak'ahs before the Maghrib prayer. He replied: I did not see anyone praying them during the time of the Messenger of Allah (ﷺ). He (Ibn Umar) permitted to pray two rak'ahs after the Asr prayer.
Abu Dawud said: I heard Yahya b. Ma'in say: The correct name of the narrator Abu Shu'aib is the Shu'aib. Shu'bah made a mistake in narrating his name.