In the time of the old testament, God allowed his prophet to listen to his word and deliver it to people. they can directly listen to what God means and he did not give them parables they did not understand. They were revealed to them so they can understand and follow the will of God. What has remained unknown was revealed when Jesus came to the earth. The things that were not yet explained was revealed but there’s a change in the new testament times.
Jesus told many parables and He did not give all of the meaning of the parable that He uttered. that is why we can see many interpretations of the bible in our age. Even if they are all classified as Christianity but they have their own interpretation to explain and support their doctrine. But all will change when the one prophesied by the Bible will appear and will reveal all the truth that was abolished even if they were established by Jesus when He came in the flesh the first time.
Reading the book of revelation, you can find the truth about the Root of David that is the only one that receives the authority to open the seal that was put in the bible. When He will open the seal, darkness would be revealed and those who listen to the voice of the shepherd will receive the truth. But those who do not listen to His voice proves that they have chosen darkness over the light. \