According to the Apostle Paul, the most prolific New Testament writer, ALL SCRIPTURE is inspired by God.
When Paul wrote his letters to Timothy, Paul referred to the Old Testament. He asserted how the Scriptures could rightly be used.
2 Timothy 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
Notice that the use of the Old Testament Scriptures is not limited to historical accounts. These Scriptures are profitable to us for doctrine, reproof, correction, and instruction in righteousness.
Many people carry only copies of the New Testament writings, with Psalms and Proverbs possibly being added. And, of course, these are inspired Words from God. We need to read them and use them for doctrine, reproof, correction, and righteousness. AND, we need the Old Testament as well. True Believers need not limit ourselves by ignoring the “inspired” Word of God. Let us never ignore or disregard ANY of God’s Words to us.
The Apostle Matthew quoted Jesus Who puts it best!
Matthew 4:4 But he answered and said, It is written, Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God.
Yes! By EVERY WORD! And, that most certainly includes the Old Testament Scriptures.