Our salvation is not contingent upon our following of the Old Testament Law. Our salvation is contingent upon the finished work of Jesus Christ on the cross and His resultant resurrection. Additionally, as we live today we are not expected to live according to the O.T. Law. Rather, God has laid out His expectations for us in the New Testament (with some input from the Old).
This brings up an interesting question: How much freedom do we have in our church gatherings?
Since Christ has set us free from the Law, can we do whatever we want when we get together? Or, are we allowed to do whatever we think is right as long as we don't specifically violate commands of scripture? Or, should we try to emulate every aspect of church meetings that we see in the New Testament?
I believe the best answer to the above question is that as we come together as the Bride of Christ we should be following principles set forth in the New Testament. While we may have some freedom in the details, we must follow the principles that God has made clear and unavoidable for us. Those principles include, but are not limited to, the following (in no particular order):
Jesus Christ is the unquestioned Head.
Gatherings are to be Holy Spirit led and directed.
Everything that occurs is to be for mutual edification.
Meetings are to essentially be family get-togethers.
The body eats together (the Lord's Supper).
Group participation is the norm.
Each person uses his or her spiritual gifts to benefit the body.
Children are present and active.
Meetings are simple, preferably in homes.
Gatherings are a time to carry out the one-anothers.
Leadership = service.
Elders come from within the body.
Meetings are free-flowing and generally unplanned (unceremonial).
Reading of scripture takes place.
Giving is to meet needs.
Decision making comes through consensus.
The above are principles were approved of by the writers of the New Testament. The Bible testifies about itself that all scripture in inspired by God (II Timothy 3:16, "All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness.") Therefore, we can and should trust that God approves of these principles and expects us to gather according to them.
So, how much freedom do we have when we gather? We have as much as we need as long as we first focus on meeting by God's principles.