On four occasions the Torah states that one must tell his child about the Exodus from Egypt, and each time it uses a different formulation. This teaches us that one must tailor his storytelling to the abilities and personality of each child.
In one place it states: “When in the future your child asks you, ‘What are these testimonies, laws, and principles that the Lord our God commanded you?’” (Devarim 6:20). The fact that he asks in a detailed manner – “What are these testimonies, laws, and principles” – implies that we are dealing with a wise child, and the verses that follow teach us that in the answer we give to the wise child we must explain at length the whole matter of the Exodus from Egypt, the mitzvot of Pesaḥ, and the destiny of the Jewish people. Therefore, the answer for the wise child is the longest and most detailed (as shown in the next section).
Elsewhere it states: “When your children ask you, ‘What is this service to you?,’ say, ‘It is a Paschal sacrifice to God, Who passed over (‘pasaḥ’) the houses of the Israelites in Egypt, when He smote Egypt and spared our homes’” (Shemot 12:26-27). This refers to the wicked son, who calls the mitzvot “work” (“avoda”), as it is difficult for him to observe them, and who says, “What is this service to you?,” as he does not feel like a participant in the mitzvot. Nevertheless, the Torah commands us to address him and explain to him Israel’s uniqueness, as expressed in the Paschal sacrifice, because we must always believe that the words may penetrate his heart and that he will gird himself with strength and faith, sanctify God’s name, and carry the torch of tradition forward.
It also states: “When in the future your child asks: ‘What is this?,’ say to him, ‘With a mighty hand God took us out of Egypt, out of the house of bondage. When Pharaoh refused to free us, God killed every firstborn in Egypt, human and beast alike’” (Shemot 13:14-15). The question “What is this?” indicates that the asker is simple and does not know how to sharpen his question. The Torah commands us to explain to him, according to his abilities, the impressive events that took place during the Exodus from Egypt, the mighty plagues that struck the Egyptians, and the hardening of Pharaoh’s heart, which was ultimately broken by the Plague of the Firstborn. These are things the simple child absorbs and finds most impressive.
Even if the child is not moved to ask at all, one must tell him about the Exodus, as it states: ““Matzot are to be eaten…. Tell your child on that day: ‘It is because of this that God did for me when I left Egypt’” (Shemot 13:7-8). Since he does not ask any questions, his interest must be aroused with tangible objects. We therefore say to him, “It is because of this” – by virtue of the matzot, maror, and Paschal sacrifice God performed miracles for us and took us out of Egypt. Thus, we put the Seder plate on the table so that each food on it can illustrate one of the meanings of the Seder night.