If we believe God’s Word is the Bible, and if we claim to be a Christian, or Christ follower, then what we are saying is that we agree to live according to His Word.
If you accept Christ as your Savior and you believe, then you are in a covenant relationship with the Almighty. A covenant is a contract, and like any contract we are obligated to obey all of the contract.
In the natural you don’t sign a contract and then only do the parts of it that you like - if you sign up you are obligated to follow all of it.
God is no different. He is patient, He is merciful, but He expects us to grow, by learning more of His word and obeying it.