Some Chassidic rebbes would take a stroll in the quiet streets on the Seder night, and listen to the Sedarim of the simple townsfolk coming through the open windows. The Bnei Yissaschar zt’l was once taking such a walk together with a few of his followers, and heard someone chant by the section of the four sons, “echad chacham, viechad rasha, viechad tam… But with each “Echad” the simple man stretched it out in the same manner as people say “Echad” in Krias Shema. The Bnei Yissaschar went inside to ask the man why he said it that way.
The man replied, “My father told me that one should stretch “Echad” by Shema, so I thought why should “Echad” in the Haggadah be different?”
The Bnei Yissacher turned to his followers, “This Yid has turned the four children of the Haggadah into the same concept as Shema.”
When people told Rebbe Yehoshua of Belz about how the Bnei Yissaschar heard the simpleton say “Echad” in the mode of Shema and that he said that the concept of the four children and saying Shema were related, he became very excited and happy about it, though he didn’t explain why. His son, Rebbe Yissacher Dov of Belz explained why his father was so happy: Chazal say that wealth and wisdom, and several other things are a matter of mazal, dependent on the mazal each person was born with. What should a person do if he was born with a mazal to be poor or foolish? Must he remain that way his entire life?
The sefarim tell that when one says “Echad” by Shema, he can change his mazal. When Rebbe Yehoshua of Belz heard that the four sons of the Haggadah also applies to the “Echad” of Shema, he understood that on this night, one has the potential to change his mazal. Even if he was born with a negative mazal, it can be improved, as he attains awareness that “Hashem Echad”- Hashem is One.
On Seder night, we seek to imbibe our children with belief in Hashem and awareness of “Hashem Echad.” ~ R’ Elimelech Biderman