The law / Torah / Pentateuch / God's commandments have never been abolished and therefor cannot be reinstituted. It is however under the new covenant of Jesus the Messiah / Yeshua ha'Mashiach's atonement offering now written on our hearts (we now want to obey God's commandments as his free sons and daughters) and not on tablets of stone anymore (when God's commandments were not yet written on our hearts).
Jeremiah 31 (ESV)
31 "Behold, the days are coming, declares the Lord, when I will make a new covenant with the house of Israel and the house of Judah,
32 not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the Lord.
33 For this is the covenant that I will make with the house of Israel after those days, declares the Lord: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people.
False Christians are not Christians that obey God's law / commandments in their walk of faith. False Christians are those that says they are Christians (followers of Christ), but who do not follow in the walk of Jesus Christ, who walked in the law of God:
1 John 2 (ESV)
4 Whoever says "I know him" but does not keep his commandments is a liar, and the truth is not in him,
5 but whoever keeps his word, in him truly the love of God is perfected. By this we may know that we are in him:
6 whoever says he abides in him ought to walk in the same way in which he walked.