In the letter to the Galatians, Paul likens the Law to a tutor or guardian over infant children. The Law taught at an elementary, childish level. But Christ treats God’s people as adult heirs (Galatians 3:23-29; 4:1-7). To go back under the Law is to return to infancy and slavery. Paul asks,
How can you turn back again to the weak and worthless elementary principles of the world, whose slaves you want to be once more? You observe days and months and seasons and years! I am afraid I may have labored over you in vain. (Galatians 4:9-11)
A similar passage in Colossians 2 shows that Old Covenant items no longer apply to Christians. In that context, Paul says,
If with Christ you died to the elemental spirits of the world, why, as if you were still alive in the world, do you submit to regulations—“Do not handle, Do not taste, Do not touch” (referring to things that all perish as they are used)— according to human precepts and teachings? (Colossians 2:20-22)
The Law used hundreds of rules and physical things to teach in an elementary way, suitable for that early, preparatory age. Why, we ask, does the New Testament have no equivalent to Leviticus and Numbers? Colossians 2:17 shows that such elemental things are merely “shadow.” “Self-made religion” based on old laws and human rules may sound wise, but they are of “no value” (Colossians 2:23). In Christ, God gives righteousness as a gift, and you respond from a true and thankful heart.