Book 1: 《學而》 Xue Er (Studying)
《學而》 Passage 1.11
子曰：「父在，觀其志；父沒，觀其行；三年無改於父之道，可謂孝矣。」
Legge Translation (1861)
The Master said: "While a man's father is alive, look at the bent of his will; when his father is dead, look at his conduct. If for three years he does not alter from the way of his father, he may be called filial."