You who seek to be justified by the Law are cutoff from Christ and have fallen out of (God’s) favor.
I personally prefer to ponder Paul’s conclusion to his argument in Galatians 5, verse 4 with the phrases reversed: You who seek to be justified by the Law have fallen out of favor and are cutoff from Christ. (And it should be here and elsewhere “Law” capitalized thereby signifying that it is the Law of Moses under discussion. It is not some general discussion of law, or of just any law you might want to consider.) In my poor mind this rendering lists the actual order of events: cause and effect. Continuing to follow after the Law would drop you out of favor with God. If you were no longer favored by The Lord of Hosts, what exactly would be in store for you?
Well then, unless I’ve wandered completely off the trail, those folks could not then and I cannot now follow or worship under either a portion of or the whole of the Law of Moses and wind up pleasing God. I cannot gain the favor of God through the Law, period. If they couldn’t, neither can we. Therefore continuing to follow the Law amounts to a rejection of what God sent along to supersede it — a rejection of The Son of God and of His Word. It no longer allows any provision for worship to God with The Christ having come, who, we are told, finished out the former covenant. It has been removed, and then, so have those who continued its practice. This was Paul’s intent when he wrote this, and it is how we must understand things now.
It would seem to follow then that I cannot grab a piece or a part of a ceremony or some bit or even an entire precept from the Old Law and toss it under, over or into the New Covenant and have those observances do anyone any good. To get from the Old to the New, Christ or His apostles and prophets would have had to have done the heavy lifting for us.
Robes, gowns, and miters, tithing, worship teaching that the Lord’s Day is equivalent to the Sabbath, or meeting in assembly on the Sabbath, or some other day in place of on the First Day of the Week, sensors and incense, ignoring NT offices and qualifications and instructions for teachers and leaders while installing priests and an episcopacy (whether male, female, or mixed), inserting organizations above or around the local assemblies, choruses, special ministries, use of instrumental music in worship (commanded in the OT, but never mentioned in the New), special programs, offering days and services, etc. etc. All of these and more lack any authority under The Christ and in His Church.
“Do not think that I came to destroy the Law or the Prophets. I did not come to destroy, but to fulfill. For assuredly, I say to you, till heaven and earth pass away, one jot or tittle will by no means pass from the Law till all is fulfilled.” (Mt. 5:17, 18)