Hebrews 3:5 (NLT2)
5 Moses was certainly faithful in God’s house as a servant. His work was an illustration of the truths God would reveal later.
Moses was faithful to God’s calling not only to deliver Israel but to prepare for the way of the Messiah. Knowing the OT is the best foundation for understanding the New Testament. In reading the OT we see (1) how God used people to accomplish his purposes,(2) how God used events and personalities to illustrate important truths,(3)how, through prophets ,God announced the Messiah, and (4) how, through the system of sacrifices , God prepared people to understand Messiah’s purpose and work.
If you include the OT in your regular Bible reading , the NT will grow clearer and more meaningful to you.