It's not disrespectful toward Jason Lisle to point out that his formal education is in astronomy and physics (good fields to be sure); however, he is not a formally trained theologian. But Jason is right that Jesus never set aside God's morality (e.g. God's moral law) which reflects God's character. In fact, God's morality is supernaturally written on the hearts of all genuine spiritually reborn Christians by none other than God.
Charles Spurgeon puts it like this:
"The fact is, that the covenant of works, if it be looked upon as a way of safety, is a total failure. No man ever persevered in it unto the end, and no man ever attained unto life by keeping it. Nor can we, now that we are fallen, ever hope to be better than our unfallen covenant-head, Adam; nor may we, who are already lost and condemned by our sinful works, dream for a moment that we shall be able to save ourselves by our works.
You see, dear friends, the firstcovenant was in these terms,—"You do right, and God will reward you for it. If you deserve life, God will give it to you." Now, as you all know right well, that covenant was broken all to pieces; it was unable to stand by reason of the weakness of our flesh and the corruptness of our nature. So God set asidethat first covenant, he put it away as an outworn and useless thing; and he brought in a new covenant,—the covenant of grace; and in our text we see what is the tenor of it: 'I will put my laws into their mind, and write them in their hearts' (Jeremiah 31:33, Hebrews 8:10, Hebrews 10:16, Romans 11:27, etc...)."
This is why we see Paul claim to have letters of recommendation not written with ink on tablets of stone but rather with the Spirit of the living God on the tablets of the human heart (2 Cor 3:2–3). Paul purposely mixed his metaphors in order to echo the prophetic passages dealing with the new covenant, in which God would replace his people’s “heart of stone” with a “heart of flesh,” put his Spirit in them (Ezek 36:26–27), and write his Law “on [their] hearts” (Jer 31:33). Thus, in 2 Corinthians 3:6 Paul claims to be a minister of a new covenant, not like the old, written covenant which “killed” by properly bringing the covenant’s curses down upon disobedient Israel, but like the covenant which Jeremiah predicted would at some future time bring forgiveness for sin and a renewed ability to know and to obey God.
As 'The Dictionary of Paul and His Letters' states:
"The Mosaic code viewed from the standpoint of its historical role in justly condemning God’s people for their sin, Paul says, has been abolished. For Paul, therefore, it is impossible to say that the Mosaic Law, minus a few cultic and ethnic regulations, is still in force. To the contrary, since the Mosaic Law was inextricably bound to a period of time in which the boundaries of God’s people were virtually identical with the boundaries of the Jewish people and to a time in which God’s people labored under a justly pronounced sentence of condemnation, it has come to its divinely appointed end (see esp. 2 Cor 3:13)."
Paul clearly states that to elevate “works of the Law” such as Sabbath keeping to the level of a requirement for living in a harmonious covenant relationship with God is to place such a relationship outside anyone’s reach, whether Jew or Gentile, because the human inclination to disobey God prevents “any flesh” from obeying the Law completely (Gal 2:16) and unless you obey the law completely you have violated all of it (James 2:10).
The second reason that “works of the Law” cannot place one within this harmonious covenant relationship with God is that the covenant of which these works are part was temporary. Unlike the promise made to Abraham, which constituted a permanent covenant fulfilled in Christ (Gal 3:15–18), the Sinaitic covenant was established “on account of transgressions.”
By this last phrase Paul means that God gave the Law at Sinai in order to reveal clearly Israel’s sin, to transform it from something ill defined and unfinished into specific transgressions against God’s will. From Galatians 4:1–5:1 Paul uses a series of metaphors to argue that those who want to live under the yoke of the covenant at Sinai, such as Sabbath keeping, are turning the clock back to an era in which both Gentile and Jew were enslaved to sin.
Playing Sabbath keeper each weekend won't get you to heaven but actually reveals you've missed the point of why Christ came and that's why Paul says in Galatians 5:14 that “the whole Law is fulfilled in one phrase, namely, ‘You shall love your neighbor as yourself,’” and in Galatians 6:2 he encourages them to bear each others’ burdens “for thereby you will fulfill the law of Christ.”
Paul makes it clear that with Christ's death and resurrection sinners are now declared righteous, not on the basis of their merits in keeping the old covenant Mosaic Sabbath law, but rather on the basis of their standing "in Christ": "There is therefore now no condemnation to those who are in Christ Jesus" (Rom 8:1 RSV; cf. Rom 3:21–31; Gal 3:11; Eph 2:8–9).
Simply put; Matthew 5:17–18, the witness of the Gospels, the earliest Christian preaching, etc... clearly reveal that Jesus “fulfilled the law” in his life, death and resurrection. He is declared as the fulfillment of Scripture. In him, the purposes of God are accomplished.
This general conviction is undergirded by the authoritative, sovereign way in which Jesus deals with specific and limiting dimensions of the law and sets his mission on a level of significance above the law. Thus, laws of separation between clean and unclean, of ceremonial defilement, of sabbath observance are set aside in the pursuit of his ministry to sinners and ritually (ceremonially) “unclean” persons. “For all the Prophets and the Law prophesied until John,” he said (Mt 11:13; Lk 16:16), indicating that a new reality, the messianic kingship, had entered the scene and was replacing the old order (Mk 1:15).
We now obey the moral law of God (e.g. God's morality), "in Christ" as Paul states so eloquently in Romans and elsewhere "No, a person is a Jew who is one inwardly; and circumcision is circumcision of the heart, by the Spirit, not by the written code. Such a person’s praise is not from other people, but from God" (Romans 2:29).
The classic text is the epistle to the Galatians, written to dissuade Christian converts from succumbing to the attempts of Judaizers to get them to adhere again to the OT ceremonial law as a necessary part of salvation. "For freedom Christ has set us free," writes Paul; "stand fast therefore, and do not submit again to a yoke of slavery" (Gal 5:1 RSV). Christ was "born under the law, to redeem those who were under the law" (Gal 4:4–5). To "rely on works of the law" for salvation is to be "under a curse" (3:10). Similarly, to place oneself under the OT law is "slavery," while choosing "the Jerusalem above is free" (Gal 4:24–25 RSV).