This is a reference to the opinion that held to the continuing legality of mutʿa in the first century and the first half of the second century of Islam, represented by Ibn ʿAbbās and the school of Mecca, which was also held by Jaʿfar al-Ṣādiq. Hossein Modarressi cites this reference to make the case that mutʿa was considered to be lawful and established by the Qurʾān and the Prophetic Sunna in the legal legacy of the House of the Prophet.
This source is part of the Online Companion to Hossein Modarressi, Text and Interpretation: Imam Jaʿfar al-Ṣādiq and His Legacy in Islamic Law (Harvard University Press, 2022).