The Old Covenant clashes very directly and sharply with New Covenant
They don't clash.
One (OT) foretold of the other (NT).
How do make these fit in with the no law NT?
Romans 2:13
For it is not the hearers of the law who are righteous before God, but the doers of the law who will be justified.
Romans 3:31
Do we then overthrow the law by this faith? By no means! On the contrary, we uphold the law.
1 John 2:4
Whoever says “I know him” but does not keep his commandments is a liar, and the truth is not in him,
John 14:15
If you love me, you will keep my commandments
2 John 1:6
And this is love, that we walk according to his commandments; this is the commandment, just as you have heard from the beginning, so that you should walk in it.
Galatians 3:21
Is the law then contrary to the promises of God? Certainly not! For if a law had been given that could give life, then righteousness would indeed be by the law.
Joshua 1:8
This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success.
Matthew 5:17
Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them. For truly, I say to you, until heaven and earth pass away, not an iota, not a dot, will pass from the Law until all is accomplished.
James 1:25
But the one who looks into the perfect law, the law of liberty, and perseveres, being no hearer who forgets but a doer who acts, he will be blessed in his doing.
Romans 3:20
For by works of the law no human being will be justified in his sight, since through the law comes knowledge of sin.
1 John 3:4
Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness.
1 John 3:21-22
Beloved, if our heart does not condemn us, we have confidence before God; and whatever we ask we receive from him, because we keep his commandments and do what pleases him.
Proverbs 28
Those who forsake the law praise the wicked, but those who keep the law strive against them. Evil men do not understand justice, but those who seek the Lord understand it completely.
Romans 13: 8-10
Owe no one anything, except to love each other, for the one who loves another has fulfilled the law. For the commandments, “You shall not commit adultery, You shall not murder, You shall not steal, You shall not covet,” and any other commandment, are summed up in this word: “You shall love your neighbor as yourself.” Love does no wrong to a neighbor; therefore love is the fulfilling of the law.
Psalms 119:10
With my whole heart I seek you; let me not wander from your commandments!
Romans 8:7
For the mind that is set on the flesh is hostile to God, for it does not submit to God's law; indeed, it cannot.
Ezekiel 36:27
And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
Romans 7:7
What then shall we say? That the law is sin? By no means! Yet if it had not been for the law, I would not have known sin. For I would not have known what it is to covet if the law had not said, “You shall not covet.”