Musnad Ahmad 435:53

Yahya ibn Ishaq narrated to us, he said: Ibn Lahi'ah narrated to us, from Ja'far ibn Rabi'ah, from Rabi'ah ibn Yazid al-Dimashqi, who informed him from Abdullah ibn 'Amir al-Yahsubi, he said: I heard Mu'awiyah ibn Abi Sufyan saying: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "If Allah, the Almighty and Majestic, intends good for a servant, He grants him understanding of the religion."