Musannaf Ibn Abi Shayba 3:5008

Waki’ narrated to us, from Yazid ibn Ibrahim, who said: Tamim ibn Salam—or Salam ibn Tamim—said to al-Hasan: "What do you say about the two rak'ahs before the Maghrib prayer?" He replied: "They are two good, two beautiful [rak'ahs] for whoever intends God by them."