Some years ago I was accused of using too much of the Old Testament. Was the accusation valid? Well, the Old Testament makes up three fourths of the Bible. It has been accepted as the word of God, so if one limits himself to the New Testament, then he would be ignoring too much of his word. When Jesus said search the scriptures (John 5:39) and Paul said the Holy Scriptures which are able to make thee wise unto salvation (II Timothy 3:15); they were both referring to the Hebrew canon.
The New Testament didn't come in a vacuum, but upon the old foundation. Any doctrine that is not in the old writings will not be found in the new. The early church did not have the writings of Paul or John, so they used what they already had. They preached Jesus, repentance, baptism in Jesus name, and the infilling of the Holy Ghost, using only the old canon. (Acts 8:32-35) (Acts 18:24-28)
Why is it that you could take away the New Testament from some preachers and they would be at a loss? How many of them could preach full salvation using only the Old Testament? I have visited some churches where even the Pastor had trouble finding scriptures in the Prophets or the Law, and could not even get the Old Testament stories right.
What is this thing, that even the pastors are often ignorant of the Old Testament? It is a shame that a man who claims to preach the Bible will almost hardly read the Old Testament or teach from it. It is like feeding people only one food group. No wonder those churches are anemic
If you are going to be a preacher of the gospel then you need to know the Old Testament too, you cannot just build a church with just part of the Bible, no, you have to use all of it. Some ministers excuse their ignorance of the Old Testament by saying that since the Law does not apply to us any longer then there is no point in studying the books of the Law. That is a big misunderstand of why we need to learn the Old Testament.
The Old Testament is more than just some outdated laws or some dusty stories, but is vitally important in order to understand the nature and person of God. God reveals himself in the Old Testament, He shows a great part of who he is and also how the people of God should behave. It gives us examples to learn what was right and what went wrong.
Yes reading the Old Testament sometimes get hard, it makes you use your brain, it forces you to think. It is not easy understanding what the prophets are talking about, the Book of Job seems to be full of some gibberish spoken by some old guys sitting around some campfire. The book of Ecclesiastes seem to be written by someone suffering from maniac depressive disorder.
From whence comes this ignorance? The rabbinical priests could close their eyes and unfold the Torah and stop at the desired text, even at the right word. They even knew exactly how many letters were in each book.
I am not advocating that we should have that kind of dedication (wish it only), but that at least we should be knowledgeable of its content. For these scriptures were also given for our profit.