People used to see dreams and relate them to the Messenger of Allah ﷺ. He said, "I see," or he said, "I hear that your dreams agree upon the last seven nights. So whoever among you wishes to seek it out, let him seek it in the last seven nights."
حدثنا إسماعيل أخبرنا أيوب عن نافع
كان الناس يرون الرؤيا فيقصونها على رسول الله ﷺ فقال إني أو قال أسمع رؤياكم قد تواطأت على السبع الأواخر فمن كان منكم متحريها فليتحرها في السبع الأواخر
No references are available.
Its isnad is sahih, and Bukhari and Muslim both narrated it with a similar meaning, as in Muntaqa 2303. See also what has already passed in the Musnad of Ibn Abbas at 2052, 2149, 2302, 2352, 3456, and in the Musnad of Ibn Masud at 4374.