If you were to pray the Rosary on a Saturday or Monday (which is a good idea) you would meditate on the joyful mysteries. The 5th joyful mystery is the Finding of the Child Jesus in the Temple.
It is one of the joys and sorrows of Mary's heart. The sorrow of losing him and joy of finding him – and it is a prelude to the Passion and Resurrection.
The search of every human heart is the search for God. If we know our body is a temple of the Holy Spirit then the Finding of the Child Jesus in the temple takes on several new meanings.
Mary and Joseph's action represents the human heart searching for God and the finding of Him in the temple shows us that we as temples of the Holy Spirit are the Father's house. Or at least we should be.
It's interesting too that this takes place while Jesus is still a child. The Divine Child brings innocence back to us. We receive the blessings of the Father when we become like little children, it's stated over and over that the Kingdom of God belongs to the little ones. It is in innocence and purity that we become the temple – the Father's house.
The symbolic nature of 3 days of searching (of which I have no doubt it actually happened too) is representative of the Trinity and dying to self so that the Trinity can dwell within you in thought, word and action. When you truly are a temple it permeates from inside of you outward and the Kingdom of God becomes apparent with the many rooms of the Fathers house seen in each and every one of us.
The scripture says his parents didn't understand what he was saying so Mary pondered all of these things in her heart. Mary is the very essence of God's temple herself because the Christ Child literally had dwelt within her. In this instance too she took what Jesus was telling her to the place where God could reveal to her the understanding of who she was and how it was she who crushes the head of the serpent. "I will put enmity between the woman and her offspring…she will crush your head..." Genesis tells us. And we too are told in Romans that "the God of peace will soon crush Satan under your feet." Mary's cooperation in the plan of God brings Victory against sin for all of us and we can all crush the serpent – as Christ claims the Victory for those he dwells within.
May the Kingdom of God dwell within the Temple of your body and soul.