The main difference between what most messianic churches teach and protestant churches teach is that the Messianic teach that all scripture must be thought of as coming from the Lord, all must be listened to. The protestant church teaches that we are now living in the new age, with a new covenant and new ways to worship.
So our current churches teach that the sacrificial system was done away with and we should not listen to it. The Messianic church teaches that the old system was of God and we need to know all about it and study it in order to understand our new life through Christ. Our church teaches all the old covenant is done with, we should ignore it as it is no longer in effect. The Messianic church teaches that we need to know all about the old covenant, we need to know what of it is obsolete, and we need to learn all about and understand the new covenant. They don't believe Constantine when he said we can not follow anything the Jews follow as they are wicked but we need to make our own like the Easter and Christmas that is made, and the new day to go to worship. To get rid of something of scripture they want it spelled out in scripture like scripture tells us about fleshly circumcision.