Musnad Abu Ya'la al-Mawsili 108:28

Ubayy ibn Ka'b led the people in prayer at Quba, and a young boy from the Ansar, who had a task to attend to, entered into his prayer. When he heard Ubayy reciting a long surah, he turned away from his prayer. When Ubayy finished, he was informed of that. Ubayy realized that the boy was going to complain to the Messenger of Allah (ﷺ), and the boy approached to complain about Ubayy. The Messenger of Allah (ﷺ) said: "Indeed, among you are those who drive people away. So when you pray, make it brief"—or he said: "make it brief" (Abu Yahya was uncertain)—"or as he said, for behind you are the elderly, the sick, and those with needs."