Faith

"Bread of Faith", that is what Matzah at the first Seder is called. By eating it we actually instill in ourselves greater faith in G-d.
The Rebbe was the epitome of faith in G-d and Torah. Every detail whether big or small was never deemed unimportant. Nothing was papered over or left to the side. G-d is true and His Torah is true.
How can we make sure that we properly take  advantage of the opportunity of the the first night's Matzah?
Yud Alef Nisson is the preparation for that, if we properly strengthen our hiskashrus we can tap into that faith. Faith in Hashem, Faith in His Torah, Faith in His Servants.