Luke 2:47-52

Luke 2:47 (KJB)
And all that heard him were astonished at his understanding and answers.

The doctors and other teachers of the law were totally amazed at the understanding Jesus had concerning the law and other spiritual things. They had realized that they were not just in the presence of a brilliant student but they realized that God was with Him in His answers. The Scripture already stated that the grace of God was upon Him.

Luke 2:48 (KJB)
And when they saw him, they were amazed: and his mother said unto him, Son, why hast thou thus dealt with us? behold, thy father and I have sought thee sorrowing.

When Mary and Joseph came into the temple, they were not astonished at His wisdom but the text states that they were relieved with joy when they finally found Him. It seemed that Jesus was insensitive to their feelings and then Mary rebukes Jesus in asking why has He dealt with them in this manner because they were searching for Him diligently and with much sorrow whenever they looked somewhere and He was not there. Mary had implied that Jesus’ actions had been irresponsible. In fact, the word for Son in the Greek used by Mary is the word used for “child.”

Luke 2:49 (KJB)
And he said unto them, How is it that ye sought me? wist ye not that I must be about my Father's business?

The response of Jesus probably brought more confusion to the situation at hand. He questioned them and asked why they were searching for Him. Then He adds a second question concerning that they should know He was about His Father’s business. In fact, the words “I must” in the Greek may be understood as “It is necessary.” Already at the age of twelve, Jesus was showing that He understood something about His coming ministry when He officially begins in 18 years. Jesus did not forsake His parents but He was obedient to the timetable God had laid out for Him.

Luke 2:50 (KJB)
And they understood not the saying which he spake unto them.

At that point Joseph and Mary did not understand the response of Jesus. They knew that Jesus had a divine calling on Him but they did not understand the particulars When Jesus presents Himself as the Messiah, He will catch His parents and the entire Jewish community by surprise.

Luke 2:51 (KJB)
And he went down with them, and came to Nazareth, and was subject unto them: but his mother kept all these sayings in her heart.

They finally left Jerusalem and returned to Nazareth. As Mary did previously, she did not just reject the sayings that Jesus made but she kept those sayings and put them in memory for now. The true meaning of all these statements would become open to them after the resurrection. Jesus was subject to His parents and showed respect to them by being obedient them until the time His ministry would begin.

Luke 2:52 (KJB)
And Jesus increased in wisdom and stature, and in favour with God and man.

During the time of the 18 years till His ministry, He did not go to India or Tibet. Instead Jesus was increasing in biblical wisdom by means of the Holy Spirit. Then He increased in stature which does not only mean that He was growing taller or was growing older but that also included the fact that He was growing in mental, spiritual, and sociological maturity. His maturity must have been pleasing to those He came in contact with while living in Nazareth because He gained favor with people plus He was growing in the way God wanted Him too for His upcoming ministry because His ways also pleased the Father.