Sunan Abi Dawud 2075
سنن أبي داود#2075HasanAbdur Rahman ibn Hurmuz al-A'raj said:Al-Abbas ibn Abdullah ibn al-Abbas married his daughter to Abdur Rahman ibn al-Hakam, and AbdurRahman married his daughter to him. And they made this (exchange) their dower. Mu'awiyah wrote to Marwan commanding him to separate them. He wrote in his letter: This is the shighar which the Messenger of Allah (ﷺ) has forbidden
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan
Muhammad Muhyi Al-Din Abdul HamidHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 12:30