Musnad Ahmad 30:1955

Hassan ibn Musa narrated to us, Ibn Lahi'ah narrated to us, Abu Yunus narrated to us, from Abu Hurairah, from the Messenger of Allah, peace and blessings of Allah be upon him, who said: "Indeed, Allah, the Almighty and Majestic, said: 'I am as My servant expects of Me. If he thinks good of Me, then it is for him, and if he thinks evil, then it is for him.'"