If you are teaching a class, to correctly quote this Bible reference, you are referring to the parable of the Prodigal Son.
Prodigal means wasteful and extravagant.
FYI, she is not teaching a class. In fact, she is taking the class (a student). Thanks for your input though
Your theme statement is not formatted correctly. First, you do not need to state "the theme of". Next, you cannot use "you" in your statement. Remember, your statement must be a profound understanding of the text. As the other commentor mentioned, keep in mind the meaning of the word prodigal. You have to pay attention to what you are saying, including spelling as well.