The Prophet ﷺ said, "Pray before the Maghrib prayer." On the third time he added, "For whoever wishes," not wanting people to take it as an established sunnah.
عن النبي ﷺ قال: صلوا قبل صلاة المغرب. قال في الثالثة: لمن شاء، كراهية أن يتخذها الناس سنة.
Bukhari narrated it in the Book of Tahajjud (1183), from Abu Muamar, who said, Abdul-Warith told us, from Husayn, from Ibn Burayda, who said, Abdullah Muzani told me the hadith, and he mentioned it. More will come in the chapter that follows this one.His words, "out of fear that people would adopt it as a sunnah," mean a fixed, regular sunnah, for it is not that. But this does not prevent holding the view that it is recommended, and this is the position taken by Imam Ahmad, Ishaq, and the scholars of hadith.