All Scripture is profitable, but we tend to overlook or maybe even altogether neglect parts of it. Usually, these neglected parts appear in the Old Testament. Often, they are “the begats,” where passage after passage relates who begot whom for many generations, for instance, I Chronicles 1-8; Ezra 2 and 10; Nehemiah 7, 10, and 12. In most peoples' Bibles, those chapters are in mint condition because they have never been read!
However, God through Paul says that the whole Bible is profitable. It is a practical and helpful tool for teachers and students alike. Scripture stands as the standard for testing everything that claims to be true. In that way, it is also our safeguard against false teaching, sounding a warning when we hear it. If we study it diligently, God's Word is a source of guidance in the right path, training us to understand how to live and do Christ's work in this world.
The apostle's words in II Timothy 3:16 tell us that we need all Scripture to function properly—even “the begats”! God put them in the Book for some good reason. By combining Scripture, the Holy Spirit, and experiences in this life, God brings a person to spiritual maturity and holiness.
When “the begats” show up in the New Testament (Matthew 1; Luke 3), as in the Old, we pay scant attention to them. We must often force ourselves to read and study those chapters. But they are there and inspired by God. He made them a part of His Word for our edification. We dare not skip over them.