——>How are folks supposed to tell which ones are still valid and which ones were done away with at the cross?
Ceremonial laws were done away at the cross (Types and Shadows).
I would focus on the law and the prophets.
Jesus gave examples in Matthew 5. Not that hard to figure out Elsie. And as I already stated, you can EXCLUDE anything related to the CEREMONIAL LAW. And, you can INCLUDE the 10 commandments (yes, all 10 of them).
All of the following, and anything related to them, are also INCLUDED:
1 Cor 6:
9Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind,
10Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.
Eph 5:
3But fornication, and all uncleanness, or covetousness, let it not be once named among you, as becometh saints;
4Neither filthiness, nor foolish talking, nor jesting, which are not convenient: but rather giving of thanks.
5For this ye know, that no whoremonger, nor unclean person, nor covetous man, who is an idolater, hath any inheritance in the kingdom of Christ and of God.
6Let no man deceive you with vain words: for because of these things cometh the wrath of God upon the children of disobedience.
19The acts of the flesh are obvious: sexual immorality, impurity, and debauchery; 20idolatry and sorcery; hatred, discord, jealousy, and rage; rivalries, divisions, factions, 21and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who practice such things will not inherit the kingdom of God.
Rev 21:
26And into the city will be brought the glory and honor of the nations. 27But nothing unclean will ever enter it, nor anyone who practices an abomination or a lie, but only those whose names are written in the Lamb’s Book of Life.
Berean Study Bible · Download
And of course, the Levitical dietary laws, which are NOT ceremonial, but instead related to God’s and our holiness (be holy, for I am holy).
Rev 22:
14Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.
15For without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters, and whosoever loveth and maketh a lie.
What does YOUR research tell you about what’s included in the “law and the prophets”?