Musnad Abu Ya'la al-Mawsili 129:33

Ubayd Allah ibn Umar narrated to us, Yazid ibn Zuray' narrated to us, Humayd narrated to us, from Anas ibn Malik, who said: A man would come to the Messenger of Allah, may Allah bless him and grant him peace, embracing Islam for something of the worldly life, not embracing it except for that. Yet, he would not reach the evening until Islam was more beloved to him than the world and everything in it.