Musannaf Ibn Abi Shayba 3:1743

Hashim narrated to us, he said: Al-Awam informed us, he said: Abdullah ibn Abi al-Hudhayl narrated to us, he said: There was an old man among those old men who used to lead his people in prayer, then he abandoned that. He said: Some of his brothers met him and said: "Why did you abandon leading your people in prayer?" He said: "I disliked that a passerby should pass by and see me praying, then say: 'These people would not have put this man forward unless he were the best of them.' By Allah, I will never lead them in prayer again."