The difficult part of preaching a seasonal service is familiarity. The familiarity of the texts and the subject matter pushes the preacher’s craft to either innovation beyond the limits of the text or simply pulling out the well-worn favorite and we all suffer through it.
When coming to a familiar text, a healthy dose of brevity mixed with homiletical restraint can stretch your preaching for several seasons on a particular text. What I mean is, rather than making all of the points in one sermon, you simply choose one point and then save the other points for years to come. This makes your development of the one point richer while also cutting down on prep in future years.
When approaching the familiar text about the lamb for the Passover sacrifice, I suggest we focus for this year on the sign of the blood of the lamb (verse 13) as the central image for the sermon. In fact, we can use an Imagistic Structure known simply as Central Image. “This sermon structure uses a single image throughout the sermon and fosters devotional contemplation of an image.” Our image will be the sign of the blood of the lamb.
“In the opening of the sermon, the preacher describes the image for the hearers. The preacher then uses that image as a source for continuing devotional contemplation throughout the sermon. The image serves as a lens through which one views the textual exposition, the theological confession, the evangelical proclamation, and the hearer interpretation of the sermon. Having a single image lends coherence to the sermon.”
In this sermon, we will begin with one of the oldest questions in the Bible: “Father where is the lamb?” (Genesis 22:7). Then, throughout the rest of the sermon we will periodically return to the image.
You may approach this structure in one of two ways: Through a single focus or a multiple focus. I am going to suggest the single focus because of the previously stated goals.
“With a single focus, the image remains the same throughout the sermon. The preacher may approach that image from a variety of perspectives (for example, viewing the same image from the perspective of different people who come into contact with it), but the image itself remains the same. Using this approach, the sermon can reinforce a single theme in a variety of situations. For example, the first encounter with the image can establish a theme and then, as the preacher uses the image again in the sermon, it can locate that theme in relation to the text and then, later, in relation to the hearers.”
Since our text is focused on establishing a tradition of ritual for right observance of the Passover, this is the area we can draw our Central Image from. Meaning there is something in their ritual which points to the Gospel in a surprising and meaningful way. In his commentary on Exodus, Brevard Childs explains it this way:
“In the Hellenistic period, Jewish exegesis and religious practice set about developing and fixing the tradition of the Passover ritual. The biblical tradition of Exodus 12 had established unequivocally the duty of a perpetual celebration of Passover which was sharply distinguished from the first Passover in Egypt. Moreover, a multitude of details regarding the precise celebration of the rite had to be settled in terms of Jewish law. What herbs were to be reckoned as ‘bitter herbs’? When precisely could the last meal with leavened bread be eaten? How was leaven to be disposed of? What was the relation of the obligation to celebrate the Passover to the observance of sabbath?” 
And for purposes of our preaching: In what way was the lamb prepared for the meal?
There was a certain way in which the lamb was prepared that makes for a powerful connection to Jesus on the cross. It points like a sign (verse 13) to the significance of what Christ did for us and what we receive in the Supper. A simple google images search of “how was the Passover lamb roasted” will show you what I mean. The cruciform nature of the way the sacrificial lamb was roasted really points towards Jesus on the cross in a visceral manner. But aside from splashing the image in a traumatic way up on a screen and talking about it while everyone feels uncomfortable, I would suggest that, in using this structure, we can craft a more meaningful reflection on the Gospel which makes the same point with more care for our listeners.
The cruciform nature of the way the sacrificial lamb was roasted really points towards Jesus on the cross in a visceral manner.
Here is a suggested outline:
- One of the oldest questions in the Old Testament was said by Isaac to his father Abraham (Genesis 22:7): “Father where is the lamb?”
- This question frames the story of salvation from the first book to the final act of the Bible (Revelation 7:10).
- Here you have Abraham being tested by taking his beloved son who was the miraculous child of the promise up a hill (where the holy of holies of the Temple would eventually be) carrying the wood for a bloody sacrifice.
- His Son asks the question we all know the answer to. The Lamb was nearly you Isaac, but God passed over Isaac on the hill and accepted a substitute (place to develop theological confession). Isaac would not be the lamb of sacrifice, but by that act it would become a sign which pointed toward another lamb.
- Take a lamb every year and make the sacrifice to remember God as Savior (verses 1-6).
- Every year they had to ask the question: Where is the lamb for the Passover this year? Every year they had to repeat this cycle repeatedly within the strict limitations of ritual observance, always remembering: “It is the Lord’s Passover. For I will pass through the land of Egypt that night, and I will strike all the firstborn in the land of Egypt, both man and beast; and on all the gods of Egypt I will execute judgments: I am the Lord. The blood shall be a sign for you, on the houses where you are. And when I see the blood, I will pass over you, and no plague will befall you to destroy you when I strike the land of Egypt. This day shall be for you a memorial day, and you shall keep it as a feast to the Lord; throughout your generations, as a statute forever, you shall keep it as a feast (Exodus 12:11-14).
- The impermanent nature of the sacrifice proves this was not THE lamb, yet! It was only a sign pointing toward a future salvation and liberation from slavery to sin and death (Hebrews 8-10).
- The point of the Passover ritual was not the doing of the sacrifice correctly. It was remembering that the God who saved in the past is the God who saves now, by faith, and would be the God who saves again in His future Messiah.
- At the beginning of the Gospel of John, the Baptizer, like a road sign, points out exactly where we can find the Lamb (John 1:29).
- Where is the lamb? Jesus is the lamb (Isaiah 53:7; 1 Peter 1:19), a theme John is glad to repeat twenty-eight times in the book of Revelation.
- But it is only a metaphor, right? It is symbolic, right? He is not really the Passover Lamb. He was not sacrificed in the same way, was He? Actually, there is a curious detail about how they roasted the lamb for the Passover sacrifice that we would do well to pay attention to. They actually roasted the lamb cruciform! Meaning they would roast the lamb on a spit in the actual shape of the cross. Listen to how Justin Martyr describes it. “That lamb which was commanded to be wholly roasted was a symbol of the suffering of the cross which Christ would undergo. For the lamb, which is roasted, is roasted and dressed up in the form of the cross. For one spit is transfixed right through from the lower parts up to the head, and one across the back, to which are attached the legs of the lamb.”
- When Jesus was on the cross, they saw the Lamb of God! Literally, they could see the Passover lamb which they had just roasted at their private ceremonies now displayed publicly on the crucified Jesus on the cross. The blood, the shape of His body, the shape His body was in! It is no wonder John puts the words of institution (curiously missing from John’s Maundy Thursday account) on the cross with Jesus the true Passover Lamb! It was not symbolic or metaphorical. Here is the Lamb of God for you... Jesus on the cross! All signs point to Jesus!
Conclusion: Here is the Lamb for you at the Supper tonight (addressing the elements for the Holy Supper)! Here is your Lamb prepared by God for your salvation from slavery to sin and death which has passed you by. Like Isaac, you get away while Jesus went the way for us! For God did not stay His hand on His beloved, only begotten son. No, He made the full and free sacrifice for you. Now, you enjoy, by Jesus’ resurrection, relationship with God and one another in the fellowship of this altar because the resurrected Jesus is truly present here with us in the Supper. He is not here metaphorically or symbolically. Listen to what Jesus says. He gives in, with, and under this bread and wine for you for the forgiveness of your sins (insert words of institution as the conclusion of the sermon).
 Brevard S. Childs, The Book of Exodus: A Critical, Theological Commentary, ed. Peter Ackroyd et al., The Old Testament Library (Louisville, KY: Westminster John Knox Press, 2004), 208.
 Taken from Dialogue with Trypho, Chapter XL.