Riyad as-Salihin 1124
Anas (May Allah be pleased with him) reported:
In the lifetime of the Messenger of Allah (ﷺ), we used to perform two Rak'ah (optional prayer) after sunset before the Maghrib prayer. It was asked: "Did Messenger of Allah (ﷺ) perform them?" He replied: "He saw us performing it, but he neither ordered us to perform them nor did he forbid us from doing so." [Muslim] .
وعنه قال‏:‏ كنا نصلي على عهد رسول الله صلى الله عليه وسلم ركعتين بعد غروب الشمس قبل المغرب، فقيل‏:‏ أكان رسول الله صلى الله عليه وسلم صلاها‏؟‏ قال‏:‏ كان يرانا نصليهما فلم يأمرنا ولم ينهنا‏"‏‏.‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏