Musnad Ahmad 26:344

Khalaf ibn al-Walid narrated to us, Khalid narrated to us, from ‘Ata’ ibn al-Sa’ib, from Shaqiq ibn Salamah, from ‘Abdullah ibn Mas’ud, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, discouraged us from conversing after the night prayer (Isha)." Khalid said: "The meaning of 'discouraged us' (jadaba ilayna) is: he criticized it, he condemned it."