Musannaf Ibn Abi Shayba 33:629

Waki’ narrated to us, he said: Malik ibn Mighwal narrated to us, from al-Sha’bi, who said: Al-Rabi’ ibn Khuthaym did not sit in a gathering since he began wearing an izar (waist-wrapper). He said: "I fear that a man might be wronged and I would not aid him, or a man might fabricate a lie against another man and I would be burdened with testifying regarding it, or I would not lower my gaze, or I would not guide someone to the path, or a pregnant woman might fall and I would not help her."