And his parents went every year to Jerusalem, at the solemn day of the pasch,  And when he was twelve years old, they going up into Jerusalem, according to the custom of the feast,  And having fulfilled the days, when they returned, the child Jesus remained in Jerusalem; and his parents knew it not.  And thinking that he was in the company, they came a day' s journey, and sought him among their kinsfolks and acquaintance.  And not finding him, they returned into Jerusalem, seeking him.
Praised be Jesus Christ!
Now and forever. Amen.
This is this fifth of the five Joyful mysteries of the rosary. I received a special request from my mother, who recently started reading my blog, that I write about this particular mystery because, out of all the mysteries of the rosary, she has the most trouble meditating on this one. Of course, I explained that I was writing about the mysteries in sequence, so I would get to this in time, but I suspect what she said about it is true for most of us. I admit, I myself really only had a surface understanding of this mystery for a long time.
Well, here I am, finally writing on it. I hope that my mom approves of the exposition I am about to write on this.
Setting the Stage
Luke begins this event by setting the historical stage, as he usually does. We are told two key things about this scene: 1) it was the feast of the Pasch (or Passover), and 2) Jesus was 12 years old. These two pieces of context lend toward helping us understand the practical, historical framework for the episode, but also the mystical and theological underpinnings to it.
Because it was the feast of the Pasch, we are given to understand both why the Holy Family were in Jerusalem (because it's not where they lived), as well as why Mary and Joseph didn't realize Jesus was still in Jerusalem for a full day after they, themselves, had left.
According to the custom of the feast, Jews were to go to Jerusalem to offer the Paschal sacrifices, and join in the Paschal celebrations. When Luke says, "having fulfilled the days," he's referring to the length of the feast, which is eight days long, beginning on the 14th of Nisan (the first month of the Jewish Sacred Calendar), and ending on the 21st.
Now, given the fact that observant Jews travelled to Jerusalem for this feast, this really represents a mass movement of people from the surrounding areas to attend the celebrations there. So, as it happens, most people travelled in caravans of friends and relatives who were all travelling to (and from) Jerusalem for the same reason. This is why Mary and Joseph missed Jesus for a whole day, because it would have been normal for the children to be with their friends and or other family members both during the feast and as they travelled.
Now, given that Jesus was still only 12 years old, we are meant to understand that He was still considered a boy at this time. A boy was considered to enter manhood at the age of 13. This means He was still fully under His parents authority, as parents, and He would not yet be participating in certain religious rites that belonged to adulthood, especially those relating to the fact that He was the firstborn. So, what we see happening here should be understood as a contextual shadow of things to come.
In Preparation of the Pasch
This whole scene should be read as a preparation for the True Pasch, which is the sacrifice of the True Lamb for the salvation of souls wrought in completion on Calvary and signified by the Resurrection. The setting for this scene, again, is the Pasch. This should alert the reader to the theological significance of the passage. The first words from Jesus that we read in the Gospel occur after the last feast of the Pasch of His childhood, and before the Paschal work of His manhood begins.
There is an ancient Jewish tradition which precedes the Paschal feast, and is meant as a preparation for it. You can find a description of it at New Advent, which is the follow:
On the evening of the thirteenth, after dark, the head of the house makes the "search for leaven" according to the manner indicated in the Mishna (Tractate Pesachim, I), which is probably the custom followed by the Jews for at least two thousand years. The search is made by means of a lighted wax candle. A piece of ordinary, or leavened, bread is left in some conspicuous place, generally on a window-sill. The search begins by a prayer containing a reference to the command to put away all leaven during the feast. The place of the piece of bread just mentioned is first marked to indicate the beginning of the search. The whole house is then carefully examined, and all fragments of leaven are carefully collected on a large spoon or scoop by means of a brush or bundle of quills. The search is ended by coming back to the piece of bread with which it began. This, also is collected on the scoop. The latter, with its contents, and the brush are then carefully tied up in a bundle and suspended over a lamp to prevent mice from scattering leaven during the night and necessitating a fresh search. The master of the house then proclaims in Aramaic that all the leaven that is in his house, of which he is unaware, is to him no more than dust.
During the forenoon of the next day (fourteenth) all the leaven that remains is burnt, and a similar declaration is made. From this time till the evening of the 22nd, when the feast ends, only unleavened bread is allowed. The legal time when the use of leavened bread was prohibited was understood to be the noon on the fourteenth Nisan; but the rabbis, in order to run no risks, and to place a hedge around the Law, anticipated this by one or two hours.
In the case of this story, the Bread that Mary and Joseph are searching for is the True Bread, Jesus, Himself. Where do they find Him? In the Temple, His Father's house.
You can see much of this tradition both in modern Easter traditions, as well as in traditional Eucharistic practices.
So, in the final year before the work of Jesus' manhood is to begin, which is a work of Passover, Mary and Joseph prepare by searching for the Bread, according to the Jewish custom.
The length of time it takes Mary and Joseph to find Jesus is also a foreshadowing of His Paschal work: 3 days. This should automatically bring the mind of the reader to Jesus' three days in the tomb. Imagine, Mary and Joseph discover that Jesus is not with their friends or family. What visions of His safety must have been rising before their eyes? They must have been terrified that He had been kidnapped, or taken by a wild animal, or some other terrible thing. In a sense, these three days of He being missing foreshadow His death.
Likewise, upon discovering Him in the Temple, and seeing that He lived, is surely a foreshadowing of His later Resurrection from the Tomb. I wonder if Mary remembered this very time as she mourned His death after the Crucifixion. What hope might she have seen there?
About My Father's Business
What may perhaps be seen as a strain of absurdity in the text is how Jesus responds to His parents' obvious worry (and perhaps anger?) after they found Him. He says, "How is it that you sought me? did you not know, that I must be about my father's business?" It might remind us of the innocence of children, who don't quite understand the terror that their parents endure whenever their safety is at risk. Children just don't think about their safety in such terms. They don't think about death. Perhaps with Jesus, we might suppose He knew He would be safe until His appointed hour, and so He really didn't worry Himself over such things.
But, of course there is theological import here. Nothing Jesus says, even as a child, is without deep meaning. And, so from this we may derive three important truths. The first is that, as a foreshadowing of Jesus' death and Resurrection, we may understand that these things, and even that which Jesus did during His time in the tomb, all of these were the "Father's business." It was the work Jesus was sent to do.
The second is that, for those who seek Jesus, He is revealing where He may be found: in the Temple, and doing His Father's work. The Temple may be understood in two ways, both as the Church itself, which He founded and which replaces the Temple as the center of Divine Worship, and the Temple may be understood to be ourselves (we are the Body of Christ, which Jesus called the Temple, which He would destroy and rebuild in three days, and we are Temples of the Holy Spirit). So Jesus is found in the Church, in other people, and in ourselves.
And secondly, Jesus may be found in the work of the Father's business. Jesus identifies with those upon whom we act ("whatsoever you do to the least of these, you do to me," for example). Therefore, it is in the work that we do, specifically in the Holy Work that we do, that we find Jesus. But, it is also in teaching, and preaching the Gospel and sound Doctrine. After all, is that not what Jesus was found doing in the Temple?
The third thing Jesus' response reveals is Jesus' own knowledge of Himself. It is not clear to Mary and Joseph what Jesus meant by this (And they understood not the word that he spoke unto them), but Jesus clearly understands His own Divine origin, as He references His "Father," who He clearly does not mean to be Joseph.
In Her Heart
There is a phrase we see here, which we have seen before (in Luke 2:19), which is that Mary "kept all these words in her heart." This is a signal to us about the origin of these stories, who is Mary, Herself. Often, you will hear the complaint that, since these events in Luke were not witnessed by the author of the Gospel, why should we accept them as true? How does he even know about them. The answer is found in the Gospel itself, included by the Gospel writer, that we might have an assurance of their accuracy. Mary kept all of these things in her heart and pondered them. It reveals her reflectiveness on these events, and also the fact that she remember them to the present day, and passed these stories on to the disciples, which is how they know about them.
I hope you enjoyed this mystery! Thanks for reading!