Jesus did not say anything to the effect that it was not good enough. Obedience to the Law of Moses has nothing to do with trying to be good enough. God has not commanded anything that is not in accordance with walking in the Spirit, but rather the Law of Moses is God's instructions for how to embody His character traits and His character traits are the fruits of the Spirit, which is they the Spirit has the role of leading us to obey it (Ezekiel 36:26-27). Again, the Law of Moses was given by God and the Spirit is God, so it would be contradictory to interpret Galatians 5:18 as referring tot he Law of Moses as if we are not led by God when we are led by God. Christ set a sinless example for us to follow of how to walk in obedience to the Law of Moses and those who are in Christ are obligated to walk in the same way that he walked (1 John 2:6).
You have the Bible available to you where God has commanded to keep the Sabbath holy, so why it makes sense to you to interpret the Bible as speaking against obeying what God has commanded is beyond me.
I speak about which law a verse is referring to only when I can justifiably make the case that it is referring to that law. Paul spoke about multiple categories of law other than the Law of God, such as with the law of sin and works of the law, so it is important to correctly discern which law he was referring to rather than blindly assume that he was always speaking about the Law of God even when he was contrasting two different categories of law with each other. For example, in Romans 7:25-8:2, Paul said that he served the Law of God with his mind in contrast with saying that he served the law of sin with his flesh and he said that the Law of the Spirit has freed us from the law of sin and death. Moreover, in Romans 8:4-7, Paul contrasted those who walk in the Spirit with those who have minds set on the flesh who are enemies of God who refuse to submit to the Law of God, so this passable should inform how to interpret Galatians 5:16-23.