The New Testament is the fulfillment of the Old Testament. The Old and New Testaments united give us the whole picture of who God is and of how He saved His children. Without the OT we would not know of the original problem of sin and how the Godhead planned a way of redemption. For it clearly reveals the character of God – His love and justice (John 3:16). The prophecies of the OT given 1000 years before Christ point to His coming while the NT tells us about the precise fulfillment of these prophecies.
The Old Testament books were the only scriptures that Christ and the disciples had and used. Jesus referring to it said, “Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfill. For verily I say unto you, till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled” (Matthew 17:18).
Jesus often quoted it as authority for the truth (John 17:17). And when meeting the temptations of Satan, He used it saying, “It is written, Man shall not live by bread alone.” “It is written again, thou shalt not tempt the Lord thy God.” “It is written, thou shalt worship the Lord thy God, and him only shalt thou serve” (Matthew 4:4, 7, 10).
He referred to its books to convince people of His mission. “Beginning at Moses and all the Prophets, [Jesus] expounded to them in all the Scriptures the things concerning Himself” (Luke 24:27). His disciples followed in His steps, “[Apollos] vigorously refuted the Jews publicly, showing from the Scriptures that Jesus is the Christ” (Acts 18:28).
Paul pointing to the importance of studying the Old Testament said to Timothy, “From childhood you have known the Holy Scriptures, which are able to make you wise for salvation through faith which is in Christ Jesus… All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness” (2 Timothy 3:15-16). Notice, Paul points that “All scripture” (Old and New Testaments) is inspired by God and applicable to all.
Finally, the Old Testament was written by holy men who were inspired by God, so, it cannot be broken “Prophecy came not in old time by the will of man: but holy men of God spoke as they were moved by the Holy Ghost” (2 Peter 1:21). It is God’s word that is needed for every generation.
In His service,