Musannaf Ibn Abi Shayba 37:465

Waki’ narrated to us, he said: Kathir bin Zayd narrated to us, from al-Muttalib bin Abdullah bin Hantab, he said: He said: "I do not fear for you one of two men: a believer whose belief has become clear, or a disbeliever whose disbelief has become evident. But I fear for you a person who seeks refuge in belief, yet acts contrary to it."