This refers to the practice of the Messenger of Allah ﷺ, meaning temporary marriage, but I fear that men would consummate such marriages with women under the arak trees and then set off with them as pilgrims.
حدثنا عبد الرزاق قال وأخبرني هشيم عن الحجاج بن أرطاة عن الحكم بن عتيبة عن عمارة عن أبي بردة عن أبي موسى أن
هي سنة رسول الله ﷺ يعني المتعة ولكني أخشى أن يعرسوا بهن تحت الأراك ثم يروحوا بهن حجاجا
No references are available.
Its isnad is sahih. Hajjaj bin Artah is trustworthy and truthful, but he practiced tadlis, and here he did not explicitly state that he heard it directly. However, hadith 351 will come by way of Shuba from Hakam bin Utayba, which removes the concern about Hajjaj's tadlis.Umara is Ibn Umayr Taymi, trustworthy. Abu Burda is the son of Abu Musa Ashari. Muslim related this hadith in 1:349 by way of Muhammad bin Jafar from Shuba, matching the isnad that will come at 351.The mutah mentioned in this hadith is the mutah of Hajj, not the mutah of marriage.