Nobody (that I’m aware of) is advocating that Christians follow ‘Pharisaical augmentations’. However, those who advocate following just the Ten Commandments and not the rest of the law have no biblical foundation. You either follow the whole law (all of the ordinances, not just the ten) or none of it. ‘613 laws’ is shorthand for ‘all the ordinances of the old covenant’; whether it is the precise number is irrelevant.
Well, like I was sayin to post, there's more than one law. And all the traditional laws of sacrificial washings and ordinances expired at the Cross.
God's Law, the decalogue (10 Commandments) did not and never will. Hence,
written in stone.
"... gifts and sacrifices, that could not make him that did the service perfect, ... which stood only in meats and drinks, and
carnal (pertaining to the flesh/external)
ordinances, imposed ...
until the time of reformation (until the time that Jesus reformed the Faith with His perfect sacrifice)."
Heb. 9:10
Jesus and Melchisedec were "... made, not after the law of a
carnal (flesh/external) commandment, but after the power of an endless (eternal) life."
Heb. 7:16
Jesus' sacrifice
did away with the carnal law, with all the commandments besides the 10, besides God's Law.
The spiritual (God's)
Law (God is a spirit - Jn. 4:24)
still remains.
"
Having abolished in His flesh the enmity, even
the law of commandments contained in ordinances; ..."
Eph. 2:15