Many times what Christ was saying in parables was hard for His disciples to understand. They understood what He was saying here about the treasure. In previous verses He told them what a normal person would do if they had found this treasure. They would sell all they had to buy it. If you have this treasure you will bring out some of what is “old and what is new”. The treasure is the Gospel of God’s mercy, love, and grace. This treasure is stored up in our heart and is bought out through how we speak, think and act. Some of what comes out seems old and are the fundamentals of the way we live out our life in purpose for Him. Some of what comes out is new – this “new” is God showing us there is more room for us to grow in our understanding and how to apply it to our lives.
Matthew 13:51
“Have you understood all these things?” They said to him, “Yes.” And he said to them, “Therefore every scribe who has been trained for the kingdom of heaven is like a master of a house, who brings out of his treasure what is new and what is old.
John 10:6
This figure of speech Jesus used with them, but they did not understand what he was saying to them
John 16:29
His disciples said, “Ah, now you are speaking plainly and not using figurative speech.
Matthew 12:35
The good person out of his good treasure brings forth good, and the evil person out of his evil treasure brings forth evil. I tell you, on the day of judgment people will give account for every careless word they speak
Psalms 119:1
Blessed are those whose way is blameless,
who walk in the law of the Lord!
Blessed are those who keep his testimonies,
who seek him with their whole heart,
who also do no wrong,
but walk in his ways