The sacrifices offered by the priests of the tribe of Levi could only cleanse the exterior, it was sufficient to make their bodies holy and clean. However, it did nothing on the inside of the priest or the individuals. That is why it had to be repeated over and over. When Jesus shed His blood, it was the perfect sacrifice, cleansing not only the body, but the heart and the conscience of each person accepting His sacrifice. Because Christ offered Himself, He gave us a new promise and established a new covenant. His perfect sacrifice will last for all ages and will never need to be repeated. Once we accept Jesus as our Savior, our place in Heaven is guaranteed forever. He has given us His Holy Spirit as an earnest, a down payment ensuring us of our heritage.