(Exodus 13:8) includes the phrase "because of this" — ba'avur zeh. The Mekhilta asks: what is the purpose of this phrase? The answer involves one of the most famous figures in the Passover Haggadah (non-legal rabbinic narrative): the wicked son.
The wicked son is identified by his question, recorded in (Exodus 12:26): "What is this work to you?" The key word is "to you" — not "to us." By asking "to you," the wicked son removes himself from the community. He speaks as an outsider observing a ritual that belongs to others, not as a participant in a shared history.
The parent's response matches the son's exclusion with an exclusion of equal force. "Because of this the Lord wrought for me" — for me, not for you. The parent adopts the same distancing language the son used and turns it back on him. You removed yourself from the community? Then the redemption does not include you. Had you been in Egypt, you would not have been redeemed.
This exchange, preserved in the Mekhilta de-Rabbi Yishmael from the 2nd century CE, became the backbone of the Four Sons passage in the Haggadah. The wicked son's question is not wicked because it is challenging — the wise son also asks a detailed question. It is wicked because it is distancing. The sin is not doubt. The sin is separation. To stand outside the community's story and say "your work, not mine" is to forfeit the redemption that belongs to those who say "ours."