D.L. Moody illustrates the concept of obedience through a story about a boy named Willie, who is asked to fetch a glass of water but instead brings grapes and oranges, thinking they would be acceptable. Moody emphasizes that true obedience to God requires us to follow His specific commands rather than offering what we think is pleasing. The sermon highlights that God desires our obedience above all else, and we cannot truly please Him without fulfilling His requests. This analogy serves to remind us that our personal preferences do not substitute for God's will.

Suppose I say to my boy, "Willie, I want you to go out and bring me a glass of water." He says he doesn't want to go. "I didn't ask you whether you wanted to go or not, Willie; I told you to go." "But I don't want to go," he says. "I tell you, you must go and get me a glass of water." He does not like to go. But he knows I am very fond of grapes, and he is very fond of them himself, so he goes out, and some one gives him a beautiful cluster of grapes. He comes in, and says, "Here, papa; here is a beautiful cluster of grapes for you." "But what about the water?" "Won't the grapes be acceptable, papa?" "No, my boy, the grapes are not acceptable; I won't take them; I want you to get me a glass of water." The little fellow doesn't want to get the water, but he goes out, and this time some one gives him an orange. He brings it in and places it before me. "Is that acceptable?" he asks. "No, no, no!" I say, "I want nothing but water; you cannot do anything to please me until you get the water." And so, my friends, to please God you must first obey Him.