Ati said, "I asked Anas bin Malik about voluntary prayer after the Asr prayer."He replied, "Umar used to strike people's hands for praying after Asr. During the time of the Prophet ﷺ, we used to pray two units of prayer after sunset, before the Maghrib prayer."I asked him, "Did the Messenger of Allah ﷺ pray them himself?"He answered, "He used to see us praying them, yet he neither commanded us to do so nor forbade us from it."
سألت أنس بن مالك عن التطوع بعد العصر، فقال: كان عمر يضرب الأيدي على صلاة بعد العصر، وكنا نصلي على عهد النبي ﷺ الركعتين بعد غروب الشمس قبل صلاة المغرب، فقلت له: أكان رسول الله ﷺ الصلاهما؟ قال: كان يرانا نصليهما فلم يأمرنا، ولم ينهنا.
Muslim narrated it in the Book of Travelers (836) via Ibn Fudayl, from Mukhtar bin Fulful, who said, then he mentioned it.As for what Tawus narrated, he said, Ibn Umar was asked about the two rak'ahs before Maghrib, and he said, "I never saw anyone pray them in the time of the Messenger of Allah," and he permitted the two rak'ahs after Asr.Abu Dawud narrated it (1284) from Ibn Bashar, who said, Muhammad bin Jafar narrated to us, who said, Shubah narrated to us, from Abu Shuayb, from Tawus, and he mentioned something similar.Abu Dawud said, I heard Yahya bin Main say, "It is Shuayb," meaning that Shubah erred regarding his name.Via Abu Dawud's route, Bayhaqi narrated it (2/476–477), and said, "The statement in such a matter is the statement of one who witnessed it, not one who did not witness it."