The moral lesson of this play needs to be understood within the context of the times in which it was written. Obedience to one's parents, particularly in the issue of marriage, is a major theme of this brilliant comedy. The play presents a very hierarchical relationship between parents and children, with parents expecting their children to be obedient. However, Goldsmith complicates this simple presentation of power, which traditionally would have been held in the hands of the parents alone, by suggesting that such obedience needs to be based on respect and love rather than unthinking servility. Parents need to act in the best interests of their children. Although it is clear that Kate and her father disagree about ideas of fashion and what she should and should not be wearing, at the same time it is clear that he wants what is best for her. By contrast, Tony deliberately disobeys Mrs. Hardcastle and does everything he can to ruin her scheme of marrying Constance to himself. Note what his first action is at the end of the play when he realises that he is legally of age:
Witness all men by these presents, that I, Anthony Lumpkin, Esquire, of BLANK place, refuse you, Constantia Neville, spinster, of no place at all, for my true and lawful wife.
This action frees Constance to marry Hastings and also frees Tony to marry whoever he pleases. Tony is allowed to frustrate his mothers plans because her desire for this marriage is shaped by avarice alone, as she wants to maintain possession of Constance's jewels and is not bothered about finding somebody who will make her son happy. The play shows that in her case she does not deserve obedience, and Tony is therefore presented as being right in resisting her plans. The moral lesson of this play therefore concerns parenting and obedience. On the one hand, children should respect the wishes of their parents, but on the other hand, parents need to earn the respect and obedience that they expect from their children.