"All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works." (2 Timothy 3:16-17).
All 66 books, the entire canon of scripture, Genesis to Revelation is the Word of God. Not just the sections in red where Jesus spoke in the New Testament, not just the miracles or the joyfulness, but the ENTIRE word of God."In the beginning was the Word, and the Word was with God and the Word was God" (John 1:1)
Since the Bible was given to us by inspiration of God, and God is perfect, naturally, the book He gave us is perfect. Continuing on in John 1:14: "And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory of the only begotten of the Father,) full of grace and truth." So the word became Jesus (God in flesh), and was here in physical form on earth - The Word = God! So I'd say it's all worth reading and applying to our lives. Even the stingy parts that contradict our ideas of right and wrong; the entire word of God is in our hands in the form of the Bible, and it should be our final authority.
The harsh part of this is that some parts of the Bible can sting, hit us hard and conflict with our sin nature (I am reminded of Hebrews 4:12 - "For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart."), and what we would like to believe is right or wrong through our own fallible perspectives. However, in Proverbs 3:5 we are told: "Trust in the Lord thy God with all thine heart; and lean not unto your own understanding" as hard as that may be at times.
In case we're ever quick to dismiss any teachings of Genesis/Exodus/Leviticus/Deuteronomy or any other book of the Old Testament because they're unpopular or because we think they don't apply to the modern day or simply because we don't like them, we have to remember that Jesus himself, several times quoted and referenced the Old Testament, saying these words: "Have ye not read?" :(ex. Matthew 12:3 & Matthew 19:4) If it was good enough for Jesus (the Word made flesh) it's good enough for us.
Additionally, Jesus being born, living 33 years and dying/resurrecting in the New Testament was not the only time the Word physically dwelt among man; we must remember that God walked on earth in the Old Testament too. He walked with Adam and Eve in the garden (Genesis 3:8) and visited Abraham in the plains of Mamre (Genesis 18:1-33) accompanied by two angels and even ate and drank with him, and discussed his decision to destroy Sodom for its reprobate iniquities. (Yes, God spoke about it. And in person).
"In the beginning was the Word..." We have the word today, in the form of the Bible. The entire God inspired book. Every chapter every verse every line is pure, and as per John 1:14 "full of grace and truth" ~ "and the truth shall make you free." (John 8:32). And whether or not it's palatable to the masses is irrelevant, every section of the book, Old and New Testament, must be made known and preached "In season out of season" (2 Timothy 4:2) - not just the parts we like.