New Covenant; Old Covenant.
Just how many ways are there to have one's sin washed away and is this like the many gospels that some think the Bible teaches?
Christian.
The Old covenant is the covenant that God had with the Nation of Israel. The church that was founded on Pentecost, as described in Acts, is under the New Covenant, and is covered with the blood of Christ. The New Covenant is what we are under today.
Are you asking about how many dispensations I see???
Aside from that: there clearly was a different aspect brought about with the introduction of the Law. The bible specifically says, "the law was a schoolmaster to bring us to Christ."