Anything relating to form, ceremony, or shadows of what Christ actually replaced - anything that doesn't relate to morals: circumcision, tithing, Sabbath days (a shadow of the rest), meats, days, oaths, dress, water baptism, etc. - all those died with Christ. Obedience to these parts of the law counts for nothing, and belies your faith in Christ's lasting sacrifice.

By his [Jesus'] sufferings, one offering, sacrifice and death, put an end to all the legal offerings, types, shadows, and figures, outward ordinances [tithes], rites and ceremonies, and many washings [baptisms], under the Law of Moses and Levitical Priesthood.
(From G. Whitehead's Letter)

If your doctor persuades you that circumcision is desirable for reasons of health, no problem; but to be circumcised to please God is a serious error. Circumcision of the foreskin is but a shadow of the circumcision we must all obtain - circumcision of the heart - to become an inward Jew.

Animal sacrifices are but a shadow of the one Christian dutiful sacrifice: the Christian's fleshly, selfish animal nature and spirit slain by the cross of Christ and presented upon the altar to God, the one true sacrifice required.

Tithing died with the new Priesthood of Christ. See Fox's writing on the details of the death of tithing.

Oaths died with Christ. Now our yes is to be yes, and our no is to be no, without any swearing, which Christ and the Apostle James strongly forbid. See Fox's writing on swearing for the details.

Regarding observing special days, Paul was tolerant, allowing that one man entertaining and regarding one day above another, and another man's days are every day alike, and about meats, and not to judge one another; "But let him, said he, be fully persuaded in his own mind;"  yet he condemns the Jewish customs and observation of days, meats, and drink. While observation of a day is a matter of individual conscience, (in which one should be fully persuaded), for a group of believers to observe a special day is definitely wrong, and a form of religion; which is condemned by Paul: But now after you have known God, or rather are known by God, how is it that you turn again to the weak and beggarly elements, to which you desire again to be in bondage? You observe days and months and seasons and years. I am afraid for you, lest I have labored for you in vain. Gal 4:9-11. And if your church leader says you should observe certain days, or certain foods, you are listening to a false prophet; as Paul says: Let no man therefore judge you in meat, or in drink, or in respect of an holy day, or of the new moon, or of the sabbath days, Col 2:16. So an individual can choose to celebrate certain days; but the church, as policy or rule, cannot; for that is a form of law. If necessary, the Lord will tell that individual continuing to observe certain days, which ones to stop; thus maintaining freedom of individual conscience.

There are entire sects built around the Sabbath as part of the Ten Commandments, insisting that worship be on the seventh day, instead of the first day of the week. Because Jesus said not one jot shall pass from the law, they think obeying all of the Ten Commandments is obeying the whole Law. The law is not just the Ten Commandments - it is hundreds of laws relating to ceremonies, rituals, ordinances, Sabbath restrictions, family life, sacrifices, washings, etc. Obeying the Ten Commandments is not obeying the Law.

And we have Paul to help us on the Sabbath controversy: Let no man therefore judge you in meat, or in drink, or in respect of an holy day, or of the new moon, or of the sabbath days: Col 2:16. You can observe your "Sabbath-day" or day of worship, any day you please; however, if you think you are righteous observing Saturday, then you need to truly observe all the laws of the old Jewish Sabbath, and you really need to observe the entire Mosaic Law. 

Whatever your "day of worship," beware of it being little more than a day of recreation, with a Quick-Stop for worship. It is better to worship on all days, in a rest from the labors of the world: namely, the pursuit of what we eat and wear. Rather let us every day rest from our old labors, and instead labor for the spiritual food that never perishes and labor for His righteousness by doing the following:

But seek ye first the kingdom of God, and his righteousness; and all these things shall be added unto you. Mat 6:33
Stop toiling and doing and producing for the food that perishes and decomposes,
but strive and work and produce rather for the food which endures unto life eternal; John 6:27
The bread that comes down from heaven - the real daily bread. John 6:27-33
Jesus replied, I am the Bread of Life. He who comes to Me will never be hungry,
and he who believes in and cleaves to and trusts in and relies on Me will never thirst any more (at any time). John 6:35
The words that I speak unto you, they are spirit, and they are life. John 6:63