Musnad Abu Ya'la al-Mawsili 245:28

Suwayd ibn Sa'id narrated to us, al-Walid narrated to us, from Thawr, from Khalid ibn Ma'dan, from Mu'awiyah ibn Abi Sufyan, that the Prophet (peace be upon him) said: "Indeed, Allah, the Almighty and Majestic, is not overcome, nor is He deceived, nor is He informed of what He does not know. Whoever Allah intends good for, He grants him understanding of the religion. And whoever He does not grant understanding, He is not concerned with him."