ʿAmr ibn ʿĀṣim said: Salām ibn Miskīn narrated to us, and ʿImrān ibn ʿAbd Allāh narrated, saying:
Saʿīd ibn al-Musayyib married one of his daughters to a young man from Quraysh. When evening came he said to her, “Tighten your garments around you and follow me.” She did so. He then said, “Pray two rakʿahs (units of prayer).” She prayed, after which he sent for her husband, placed her hand in his, and said, “Take her.” The young man left with her. When his mother saw the bride she asked, “Who is this?” He replied, “My wife.” She said, “May I never face you again if you touch her before I prepare her in the proper manner accorded to the women of Quraysh.” She therefore readied her, and afterwards he consummated the marriage. (1)

Among the signs of his skill in interpreting dreams:
Al-Wāqidī said: “Saʿīd ibn al-Musayyib was one of the most proficient people in interpreting visions; he learned the art from Asmāʾ bint Abī Bakr al-Ṣiddīq, and Asmāʾ had learned it from her father.”

Al-Wāqidī then related several dreams, among them (2):

Mūsā ibn Yaʿqūb narrated to us, from al-Walīd ibn ʿAmr ibn Musāfiʿ, from ʿUmar ibn Ḥabīb ibn Qulayʿ, who said:
“I was sitting with Saʿīd ibn al-Musayyib one day when my affairs were straitened and I was burdened by debt. A man came and said, ‘I saw in a dream that I had seized ʿAbd al-Malik ibn Marwān, laid him flat on the ground, pinned him down, and drove four pegs into his back.’

Saʿīd asked, ‘Were you the one who saw this dream?’
He replied, ‘Yes, indeed.’
Saʿīd said, ‘I will not explain it to you unless you first tell me who sent you.’
He answered, ‘Ibn al-Zubayr saw the dream and sent me to you.’
Saʿīd said, ‘If his vision is true, ʿAbd al-Malik will kill him, and from the loins of ʿAbd al-Malik will come four men, each of whom will become caliph.’

“So I travelled to ʿAbd al-Malik in Syria and informed him. He was pleased, asked me about Saʿīd and his circumstances, and when I told him, he ordered my debt to be paid, and I received good from him. (3)