Most Christians believe it was moved to the first day of the week, as the confession states:
> VII. As it is the law of nature, that, in general, a due proportion of time be set apart for the worship of God; so, in his Word, by a positive, moral, and perpetual commandment binding all men in all ages, he has particularly appointed one day in seven, for a Sabbath, to be kept holy unto him:[34] which, from the beginning of the world to the resurrection of Christ, was the last day of the week: and, from the resurrection of Christ, was changed into the first day of the week, which, in Scripture, is called the Lord's Day, and is to be continued to the end of the world, as the Christian Sabbath.
Citing:
> [35] GEN 2:2 And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made. 3 And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made. 1CO 16:1 Now concerning the collection for the saints, as I have given order to the churches of Galatia, even so do ye. 2 Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that there be no gatherings when I come. ACT 20:7 And upon the first day of the week, when the disciples came together to break bread, Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight.
(though Seventh Day adventists believe it should still be on Saturday)
There are a range of views regarding the Sabbath in the Christian tradition, as well as the rest of the original law. A common view amongst the reformed is that the law is divided in 3 parts: the civil law, the ceremonial law and the moral law. On this view the ceremonial law was fulfilled in Christ, the civil law can stand as a guide for how we structure government (but not necessarily a requirement), and the moral law is still binding for Christians.
Somewhat related to the three uses of the law:
1. The usus politicus sive civilis, the political or civil use, is a restraint on sin and stands apart from the work of salvation. It is part of God's general revelation or common grace for unbelievers as well as believers.
2. The usus elenchticus sive paedagogicus, the elenctical or pedagogical use which confronts sin and points us to Christ.
3. The usus didacticus sive normativus, the didactic use, which is solely for believers, teaching the way of righteousness.
Some view the Sabbath as part of the ceremonial law, and others that it is part of the moral law. For a longer-form discussion on this issue consider Michael Horton's "Are we Required to Attend Church on Sunday": https://www.whitehorseinn.org/2011/12/are-we-required-to-att...
> As I said, what I don’t know about the daily practice of Christianity could fill volumes, but outside of some obvious cherry picking of Leviticus it seems that they have their own thing going.
I wouldn't entirely disagree with this, Christians often ignore the Old Testament... but there's a very rich tradition of Old Testament commentary related to Biblical Theology. Consider Peter Leithart, interpreting the Old Testament in light of the New: https://youtu.be/vr1oH4hpl5Q?t=358
> Thomas can spin off sanctuary typologies with the imaginative verve of an Origen or a Bede. According to Thomas, “the figurative reason” for the specific features of the tabernacle and its furnishings “may be taken from the relation of the tabernacle to Christ, who was foreshadowed therein.” Christ is typified by the “propitiatory” or mercy seat, which, in Thomas’s understanding, was borne aloft above the cherubim, figuring the angels who exalt Jesus. Jesus is the new ark: “As the ark is made of setim-wood, so is Christ’s body composed of most pure members,” and as the ark is overlaid with gold, so “Christ was full of wisdom and charity, which are betokened by gold.” The golden pot inside the ark represents Christ’s “holy soul” and is full of manna because “all the fullness of the God” dwells in Him. Since Jesus possesses priestly power, He is fittingly represented by the rod of Aaron; since He is a lawgiver, He is foreshadowed in the tables of Torah. That “Christ is signified by the candlestick” is evident from John 8 (“I am the light of the world”), and the seven lamps on the stand represent the seven Spirits of God that come from the Lamb in Revelation. Jesus is the table of showbread, since He says “I am the living bread.” Christ is figured by the two altars of the tabernacle, since all our works are offered to God through Him. In Christ we offer our afflictions to God on the altar of holocausts, and perfected Christians offer their spiritual desires to God in Christ “on the altar of incense.” Nearly every detail of the tabernacle serves as a type of the incarnate Son in His Person and His work of propitiation and intercession.
In particular his commentary on 1 and 2 Kings is fantastic.