Sayyiduna Shaddad (may Allah be pleased with him) went in to Sayyiduna Mu'awiyah (may Allah be pleased with him) while he was sitting and Sayyiduna Amr bin al-As (may Allah be pleased with him) was on his bed. Shaddad (may Allah be pleased with him) sat down between the two of them and said: Do you both know what made me sit between you? I heard the Messenger of Allah (peace and blessings be upon him) say: "When you see the two of them together, separate them, for by Allah, they never come together except for some treachery." So I wished to separate the two of you.
Hadith Referenceالمعجم الكبير للطبراني / باب الشين / 7130