Analects 2.4-5 · WEI CHANG
The Master said, 'At fifteen, I had my mind bent on learning. 'At thirty, I stood firm. 'At forty, I had no doubts. 'At fifty, I knew the decrees of Heaven. 'At sixty, my ear was an obedient organ for the reception of truth. 'At seventy, I could follow what my heart desired, without transgressing what was right.' Mang I asked what filial piety was. The Master said, 'It is not being disobedient.' Soon after, as Fan Ch'ih was driving him, the Master told him, saying, 'Mang-sun asked me what filial piety was, and I answered him,-- "not being disobedient."' Fan Ch'ih said, 'What did you mean?' The Master replied, 'That parents, when alive, be served according to propriety; that, when dead, they should be buried according to propriety; and that they should be sacrificed to according to propriety.'