On the Seder night we are confronted with a wealth of forms, symbols, complicated customs and rituals, and several different phases of Jewish history.
At the root of all this richness and variety, however, lies one central idea that binds the Seder’s disparate parts into a single whole:
“Once we were slaves—now we are free.”
On the night of Passover, this idea of freedom is given full expression in the Haggadah: in ritual and symbolic acts, in poetry, and in the overall atmosphere of the evening.
The Haggadah is not a philosophical treatise, yet ideas of great profundity are expressed in its most uncomplicated forms, through simple words and actions.
The significance of these acts is bold and striking, making its way, consciously or not, into the souls of those who participate in them.
–Rabbi Adin Steinsaltz