When God gave His People the Passover ceremony about three and a half millennia ago, at the time He brought Israel up from the land of Egypt, He gave this observance to point forward to His Messiah, Whom He would send to make a greater freedom available from a far worse slavery. So at the Lord's Passover Seder (or supper) which He commanded through Moses, He taught about the coming Messiah not only through words, but also through symbols that would be tasted, smelled, touched and seen. This use the five senses makes and unforgettable impression to prepare Israel to think deeply and creatively about Him in preparation for His arrival.
Not to be ignored is His use of the sense of smell. The smell of the maror and the haroses, and in former times, the delicious smell of the roasting lamb, weave themselves into the warp and woof of a Jewish person's awareness of life. The olfactory nerves, which carry smell sensations to the brain, enter the brain very near the limbic system, the part of the brain that relates to emotions. For that reason, smells are more difficult to learn than are other kinds of sensations. But once they are learned, they are never forgotten and are especially effective at bringing back whatever emotion we have associated with that smell. Notice, please, in your own experience, how powerfully certain odors can bring out a predictable emotional response in you. (In the old days, psychologists used to call the limbic system the "rhinencephalon", which is Greek for 'nose-brain'.) So He uses the sense of smell as a teacher about His Messiah.
And, speaking of the nose, He uses the maror (translated 'bitter herbs' in your English Bible, labeled 'horseradish' in your grocery store) to make the nose and eyes to run and to help His People remember by taste how bitter is the life of slavery. After a taste as bitter as maror, almost anything tastes sweet, including plain water. Likewise, even plain water tastes a little bitter after the sweet taste of the haroses reminds the tongue of the sweetness of our Messiah's Freedom. (Incidentally, sour and salty things have this same kind of opposing effect.)
And on the subject of sweetness, there's the Passover lamb. Back when the Temple was standing in Jerusalem, that sacrifice must have torn its way into every Jewish heart. Even in a modern slaughterhouse, I'm told, it's very hard to keep slaughterers in the lamb chop section. The stress is too much. The lamb comes in playing happily and licks the hand of the slaughterer. It's quite an experience to have to cut the throat of such a gentle, trusting baby. But what would it be like if the lamb you had to kill was the lamb you had nurtured and cared for yourself, dying as a sacrifice for you? And then imagine that you were to dress, roast, and eat that lamb yourself. And then feel your own insides digesting that lamb, making that gentle, innocent lamb your own internal strength as you and the lamb become completely identified with each other. What a teacher the God of Israel is!
Most Jews this Passover will touch the matzah, the unleavened bread, and feel its stripes, its "bruises", and the holes where it's been pierced. And they'll break it and pray, "Blessed are you, Lord our God, King of Eternity, Who brings forth bread from the earth." Please pray that every Jewish family will soon trust the Bread of Life Whom God resurrected from the earth for them.