Ramayana
मातरं पितरं यो हि आचार्यं चावमन्यते । स पश्यति फलं तस्य प्रेतराजवशं गतः ॥ 7-15-21 ॥
He who slights his mother, his father, and his teacher sees the fruit of that when he has fallen under the sway of Yama, the king of the dead.
english translation