The Old Covenant was an agreement between God and Man while following the instructions and guidance of the Lord. They were also instructed to keep faith in God’s word and be obedient to his word. There was a High Priest appointed from among Men to be a buffer between God and Man. The High Priest would offer up gifts and sacrifices to God and remind man of their sins committed against God. Since Man was unable to give their own blood as a sacrifice, they gave the blood of animals [such as goats or cattle] as a sacrifice to the Lord. The High Priest was also unable to forgive Man of their sins; they were only able to remind them of their sins that had been committed against God. The blood and ashes of the animals was used to purify the gifts offered to God.
Jesus was the Author and Creator of the New [Living] Covenant. The New [Living] Covenant was needed because there was a weakness in the Old Covenant. God’s “Only Begotten Son”, [pertaining to being the only one of its kind within a specific relationship], was sent to be the Son of Man in order to forgive Man of his sins. Before coming to earth and being chastised and tempted, he came through Heaven. Because of this, he was able to offer eternal salvation all who would receive. He was crucified, hung on the Cross where he died. He was buried, but rose from the grave to save Man from his sins. Not only was Man’s sin forgiven, the sins were forgotten, never to be remembered again. If Man had been able to save himself from sin, we would not need the New Covenant. After Jesus was resurrected he went back to live with his Father but, he left a comforter with Man for as long as he believed in God and remained faithful to his word. This comforter was the Holy Spirit which gave Man a direct connection to Jesus Christ the Son of God because no Man can see the Father unless they go through Christ Jesus.