I believe that throughout the Bible we see God gradually revealing himself. The revelation is slow and gradual. The fullest revelation of God and of God's teachings are through Jesus Christ and I am sure we do not fully understand all of his teachings. Certainly his disciples did not fully understand. Certainly Paul did not fully understand as he defended slavery. Gradually over the centuries mankind has gained a bit more understanding, but it is not full nor complete. In my opinion we still have a long way to go. But what does this have to do with interpreting scripture? Just this, IMHO. Any interpretation of any portion of scripture that conflicts with the teachings of Jesus or the way Jesus lived his life, is an interpreting error. All interpretation of scripture, whether it be OT or NT must fit within the teachings of Jesus and must fit within the example he showed in the way he lived.