“Therefore every teacher of the law who has been instructed ...” (Matthew 13:52)

“Therefore every teacher of the law who has been instructed about the kingdom of heaven is like the owner of a house who brings out of his storeroom new treasures as well as old.” (Matthew 13:52)
After explaining the "kingdom of heaven" - using a number of parables, Jesus speaks about spiritual teachings. What does he mean?

What is a 'teacher of the law'?

Who is Jesus referring to as the teacher of the lawhere? This phrase is being translated from the Greek word γραμματεύς (grammateus), which means "a religious teacher" according to the lexicon.

The use of the phrase, "the law" is a bit deceiving because Jesus was not referring to lawyers. But it is notable that the temple priests during Jesus' time interpreted the "law" of Moses - considered the law of the land in most of Judea. So "teacher of the law" could be interpreting Mosaic law.

But Jesus was utilizing this word beyond simply the priests of the temple institutions. Within this context, Jesus is referring to those who would be passing on spiritual teachings.

This long-standing tradition, in which Jesus was involved, passed on spiritual knowledge via a lineage of spiritual teachers from teacher to student.

What does he mean by 'kingdom of heaven'?

So what is the "kingdom of heaven" as Jesus refers to here? The word "kingdom" is being translated from the Greek word βασιλεία (basileia) meaning "royal power, kingship, dominion, rule; not to be confused with an actual kingdom but rather the right or authority to rule over a kingdom."

Thus, "kingdom" relates to the consciousness of perceiving the Supreme Being's greatness. And the "kingdom of heaven" refers to that consciousness of loving and serving the Supreme Being - which is the consciousness of those within the spiritual realm.

What does the 'owner of a house' symbolize?

Now Jesus is introducing an analogy. Because Jesus uses "is like," we know the "owner of a house" is being compared to the person who is teaching the word of God - passing on those teachings he has been given.

Such a person "brings out of his storeroom" the teachings that he has been given by God and God's representative. The "storeroom" is thus his heart - because that is where those teachings ultimately come from. They might have been retained in the memory of the person, but the person who is teaching others about the loving relationships of the spiritual realm - those dedicated to pleasing and serving the Supreme Being - is bringing those teachings out from within his heart.

What are the 'new treasures'?

The “new treasures as well as old” represents a combination of teachings that have been passed down through the lineage of ancient teachers, and those that come from the heart of the living teacher.

Both of these should be congruent. A teacher who represents the teachings of the Prophets but comes up with their own speculative teachings about today would be misleading. True teachings are congruent with scripture and the heart, along with the reality of observation.

Jesus and his disciples were passing information given through an ancient lineage of devoted spiritual teachers. These included John the Baptist, Jeremiah, Isaiah, Job, Malachi, Solomon, David, Samuel, Eli, Joshua, Moses, Isaac, and Abraham. Thus those teachings represent and reveal the loving service relationships between these exalted persons and the Supreme Being.

God's representative will also teach from within his own heart - revealing his love and loving service relationship with the Supreme Being:
I will teach you about the power of God; the ways of the Almighty I will not conceal. (Job 27:10-12)

My son, do not forget my teaching, but keep my commands in your heart... (Proverbs 3:1-3)

Keep my commands and you will live; guard my teachings as the apple of your eye. (Proverbs 7:1-3)

So that your trust may be in the LORD, I teach you today, even you. (Proverbs 22:18-20)
What were all these teachers teaching if Jesus is the only teacher? They too were, as was Jesus, passing on God's teachings. This is clarified by Jesus when he said:
"My teaching is not my own. It comes from Him who sent me." (John 7:16)
These statements show that Jesus - and God's messengers in general - have been teaching what the Supreme Being asked them to teach. Therefore, ultimately, it is God who is teaching us through His messengers.

This is contrary to many institutional teachers today who instruct their parishioners that Jesus was the only teacher and to have no other teacher but Jesus. 

How can they teach that Jesus was the only teacher?

Such an instruction is hypocritical. Why? Think about it: A person is taking the role of teacher, and teaching that we should accept no other teacher other than Jesus. The teacher is teaching something. Therefore they are being the teacher and asking us to listen to them. Then they are teaching that we should have no teacher but Jesus. Does that make any sense? It would only make sense if they were Jesus. 

But they're not Jesus.

A person who has no real authority or empowerment to represent the Supreme Being can certainly parrot the slogans of their official church or organized sect. But this doesn't make them representatives of God. Even if they are wearing the official suits: The white collar, the big hat, and/or the flowing robes:

Such coverings can also be masks that cover their real mission: They may want to be honored by others. They may want to tell others what to do. They may want to receive acclaim and respect. And they may also want to be paid their minister's salary - a sign they are servants of money and a desire to have many followers. These traits are contrary to being a servant of God.
"Beware of the teachers of the law. They like to walk around in flowing robes and love to be greeted in the marketplaces and have the most important seats in the synagogues and the places of honor at banquets." (Luke 20:46)
Like the Pharisees that criticized and persecuted Jesus, the professional ecclesiastical teachers of today in the guise of priests, preachers, ministers, and reverends have no real authority from God because they are representing these organizations, and being paid to say what they say:
Her leaders judge for a bribe, her priests teach for a price, and her prophets tell fortunes for money." (Micah 3:10)
Such professional priests and reverends already receive their reward in the form of their salaries and their supposed followers.

God's messenger will typically not be part of any elected church or professional position. They will not accept such a position because they know it contradicts devotion to the Supreme Being.

In order to teach, a person must first be a student. Even Jesus took the position of student under John the Baptist. Jesus heard John's teachings and then he applied those teachings. The position of being a student before teacher was, in fact, one of Jesus' most important lessons:
"A student is not above his teacher, but everyone who is fully trained will be like his teacher." (Luke 6:39-41)
Jesus asked that anyone who truly heard from him and applied his teachings pass those on to others.

Jesus confirms this:
"Anyone who breaks one of the least of these commandments and teaches others to do the same will be called least in the kingdom of heaven, but whoever practices and teaches these commands will be called great in the kingdom of heaven." (Matthew 5:18-20)