When Ali sent Ammar and Hasan to Kufa to rally the people, Ammar addressed them and said, "I certainly know that she is his wife in this world and in the hereafter, but Allah has tested you to see whether you will follow him or her."
حدثنا محمد بن جعفر حدثنا شعبة عن الحكم قال سمعت
لما بعث علي عمارا والحسن إلى الكوفة ليستنفراهم فخطب عمار فقال إني لأعلم أنها زوجته في الدنيا والآخرة ولكن الله عز وجل ابتلاكم لتتبعوه أو إياها
Its isnad is sahih. It is found in Bukhari, 5/106, in the chapters on the virtues of the companions of the Prophet ﷺ, the virtue of Ayesha.