I like to study the bible by cross referencing scriptures throughout the bible, from OT to NT.
This way, we can get a better understanding of what God says about any particular topic. Scripture says by two or more witnesses His word is established, and by multiple authors all inspired by the Spirit of God, the bible establishes God's meaning alone without the need for commentary and man's interpretation.
However, as NT believers we do need to understand the spiritual application of the Law and how it points to Christ Jesus and what He would accomplish. The Law has not been destroyed or eliminated for NT believers, but we walk in the spiritual understanding and application of the Law as it has been written in our hearts and minds. The Ritual and Ceremonial Law now apply spiritually and not by the letter. The Moral Law has always been spiritual and thus still applies.
Using a concordance and Lexicon are great tools for study. As we do study His scriptures from OT to NT we can consult a concordance and lexicon to get a better understanding about words being used.