Unlike certain cultural icons today, Jesus didn't preach what people's itching ears wanted to hear. He didn't cater his sermons to curry favor with the popular culture. He articulated a higher standard of morality than even the Old Testament did.
More importantly, He did not reject but wholeheartedly endorsed the Old Testament generally and specifically. He didn't come to abolish the law but to fulfill it. He said that "until heaven and earth pass away, not an iota, not a dot, will pass from the Law until all is accomplished," "the scriptures cannot be broken," and, "I am the God of Abraham and the God of Isaac, and the God of Jacob."
Jesus also affirmed the historicity of many important events recorded in the Old Testament, which many today dismiss as mere allegory or pure fiction, such as the creation of Adam and Eve, the flood, Jonah and the whale, the miracles of Elijah, and the miracles of Moses in the wilderness.
His sinless life and His teachings, crucifixion and resurrection didn't render the Old Testament irrelevant but affirmed it as pointing to Him.
New Testament writers also affirmed the authority of the Old Testament. The Apostle Paul said, "All scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work."
Both Old Testament and New Testament writers asserted they were speaking on God's behalf and that what they were recording was factually and historically true.
Moses said his writings were from God, and the Old Testament prophets claimed to be speaking the words of the Lord.
Luke said, "Since I myself have carefully investigated everything from the beginning, it seemed good also to me to write an orderly account for you, most excellent Theophilus, so that you may know the certainty of the things you have been taught."
Peter said, "We did not follow cleverly invented stories when we told you about the power and coming of the Lord Jesus Christ, but we were eyewitnesses of his majesty."
Paul said, "I want you to know, brothers, that the gospel I preached is not something that man made up. I did not receive it from any man, nor was I taught it; rather, I received it by revelation from Jesus Christ."
It's bad enough that some people are caving to cultural pressure to dismantle traditional values, but could we please not throw the Bible overboard in this frantic stampede to be loved by the culture?