Is the Old Testament to be used in the "modern" church? If the Old Testament was removed from our doctrine, we could no longer understand Creation, the Ten Commandments and grace of God. Equally important, we would not comprehend the nature of Jesus Christ. It was Jesus speaking of the Old Testament that said...
John 5:39 Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.
Matthew in writing Matthew 28:19 wrote that we are to be baptized in the name of the Father, Son and Holy Ghost. The disciples understood this command and baptized in the name of Jesus Christ (Acts 2:38, 8:16, 10:48, 19:5) because of their study of the scripture. There is no contradiction because the Old Testament reveals that Jesus Christ is the Father.
Isaiah 9:6 For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace.
The Apostle Paul in writing to Timothy gave sound advice in concerning the Bible, but at the time of his writing he was speaking of the Old Testament.
2 Timothy 2:15 Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.
The Amplified Bible states, "Accurately handling and skillfully teaching the word of truth". We can not pick and choose our doctrine to fit our desires or the desires of a crowd. My dad (and pastor) says that we can not have a "cafeteria-style religion". In the same letter that Timothy is told to study, Paul writes that there will be those that will choose the doctrine that pleases them.
2 Timothy 4:3 For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears;
The Amplified Version states:
2 Timothy 4:3 For the time will come when people will not tolerate sound doctrine and accurate instruction [that challenges them with God’s truth]; but wanting to have their ears tickled [with something pleasing], they will accumulate for themselves [many] teachers [one after another, chosen] to satisfy their own desires and to support the errors they hold
The Old Testament is God's Word. We do not sacrifice animals but when the Word is rightly divided, we understand why. We no longer believe an "eye for an eye", but when we rightly divide the Word it is understood.
The Old Testament teaches us the true nature of Jesus. We can understand the pattern of salvation because of the Tabernacle. It allows us to see the mercy of God in the cities of refuge and it our basis for a life of separation from the World. Yes, the Old Testament is for the modern church.
Matthew 5:18 For I assure you and most solemnly say to you, until heaven and earth pass away, not the smallest letter or stroke [of the pen] will pass from the Law until all things [which it foreshadows] are accomplished. (Amplified Version)