ייִדישער מחשבֿה אויף מלאכי 1:6

Nevertheless, the Torah and reason impose upon children the duty of serving, honoring and revering their parents, as Scripture says: "Ye shall, everyone, revere his father and his mother" (Vayikra 19:3); "Hear, O my son, the instruction of your father and forsake not the law of your mother" (Mishlei 1:8) ; further, "A son honors his father, and a servant his master" (Malachi 1:6). (And these duties are enjoined) despite that the father is impelled by a natural instinct and the benefaction comes from G-d, while the parent is only the agent.

The kindness of a master to his servant: It is obvious that the master's intent is to improve his property by an outlay of capital, since he needs his servant's work, and his motive in this is to further his own interest. Nevertheless, the Creator, blessed be He, imposes upon the servant the duties of service and gratitude, as it is said, "A son honors his father and a servant his master" (Malachi 1:6).