'He said to the them, '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 verse 52
The secret in this verse is 'who has been instructed'. To draw treasures out of our own lives we must become teachable; take instruction from Christ Himself. If we never learn, then we can never teach. The best kind of teacher is the one who is teachable.
No matter how long we have been on the spiritual road we are always learning, for we are 'pressing into the kingdom'. Luke 16 verse 16.
Then when a friend comes to us, even at midnight, we will have new treasures as well as old to give him.