The Meaning of Reverence

What constitutes fear? One must not stand in the place appointed for his father, in a council of elders or the place reserved for him to pray. One must not sit in the seat generally occupied by his father. One must not contradict his father's words nor corroborate his words in his presence (even to say "father's opinion appears correct"), nor call him, while alive or dead, by his name.

To what lengths should the duty of revering parents go? Even if he is attired in costly garments, presiding over a meeting, and his parents come and rend his garments, strike him on the head and spit on his face, he must not shame them but should remain silent and fear the King of kings, the Holy One, blessed is He, who has thus decreed. For if a mortal king were to issue a decree against him, even more exasperating in character, he would be powerless to rebel against it; all the more so if the author of the decree is He by Whose word the world came into being in accordance with His will [Ibid, 240:2f.; Hilchos Mamrim 6:7].