Here, Christ's instruction to watch continues. However, this time Jesus focuses specifically on the responsibility of the steward—the one given authority over the household while the Master is away. His theme is preparation and faithful continuance of duty. He tasks the steward—a type of the ministry—with giving the household "food in due season."
Similarly, Paul outlines the responsibilities of church leadership in his letter to the Ephesians. Notice that the focus is on the church, not on the world: "And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry [service], for the edifying of the body of Christ. . ." (Ephesians 4:11-13). Church leaders are responsible for feeding and preparing God's household and encouraging them to watch themselves.
If the steward does not properly watch, however, the human proclivity is to let down—and abuse. The steward in Luke 12:45 is focused on the Master's return—or lack thereof—rather than on his own alertness and attention to his duties. As a result, he falls into excesses of eating and drinking (rather than providing food for the household). He ends up beating those he was supposed to watch over, as if he thought they belonged to him. Clearly, those who have stewardship responsibilities in the church have an added weight to "take heed to themselves" lest they neglect or even damage those for whom they are supposed to be providing spiritual food.