there was a big change

Hebrews 9

v8,9

The Holy Ghost this signifying, that the way into the holiest of all was not yet made manifest, while as the first tabernacle was yet standing:

Which [was] a figure for the time then present, in which were offered both gifts and sacrifices, that could not make him that did the service perfect, as pertaining to the conscience;

Continuing through these chapters in Hebrews, I continue to see this series of passages clearly teaching that our covenant with the Lord has changed. We are not supposed to have exactly the same kind of approach to the Lord, now that Christ has come, died on the cross, and risen again. The old covenant was temporary and incomplete, and the new covenant is different and meant to supersede it.

v8 said, ...the way into the holiest of all was not yet made manifest... That means that, living under the old covenant, you wouldn't quite get the whole picture, yet. The old covenant was not perfect and complete by itself. v9 says it [was] a figure for the time then present..., which means that the old covenant was temporary, and it is not supposed to be imposed on us any more today. It was not the actual substance but it was just a figure. The old covenant ...could not make him that did the service perfect... like we can be perfectly cleansed from sin by the blood of Christ today.

So this means that we definitely need see that there has been a big change since the Old Testament, and a new way has been revealed to come to God by faith in Christ. Beware that you don't try to have the traditions of the Old Testament laws (only eating certain kinds of food, observing holy days, having a line of human priests, etc.) imposed on your life in an attempt to be justified to God. That would be using those things wrongly, because they were meant to be symbolic, and they have been fulfilled in Jesus.