It's your argument. Support your case. It's not about my understanding, it's about yours.
When Adam and Eve sinned and disobeyed God it showed a lack of Trust in God, Satan basically said God was withholding something from them and couldn’t be trusted.
Now as you can see the Israelites in the wilderness are given commands and laws, will they trust God and obey Him and receive the promised land and blessings?
““Every commandment which I command you today you must be careful to observe, that you may live and multiply, and go in and possess the land of which the Lord swore to your fathers. And you shall remember that the Lord your God led you all the way these forty years in the wilderness, to humble you and test you, to know what was in your heart, whether you would keep His commandments or not. So He humbled you, allowed you to hunger, and fed you with manna which you did not know nor did your fathers know, that He might make you know that man shall not live by bread alone; but man lives by every word that proceeds from the mouth of the Lord. Your garments did not wear out on you, nor did your foot swell these forty years. You should know in your heart that as a man chastens his son, so the Lord your God chastens you. “Therefore you shall keep the commandments of the Lord your God, to walk in His ways and to fear Him. For the Lord your God is bringing you into a good land, a land of brooks of water, of fountains and springs, that flow out of valleys and hills; a land of wheat and barley, of vines and fig trees and pomegranates, a land of olive oil and honey; a land in which you will eat bread without scarcity, in which you will lack nothing; a land whose stones are iron and out of whose hills you can dig copper. When you have eaten and are full, then you shall bless the Lord your God for the good land which He has given you. “Beware that you do not forget the Lord your God by not keeping His commandments, His judgments, and His statutes which I command you today, lest—when you have eaten and are full, and have built beautiful houses and dwell in them; and when your herds and your flocks multiply, and your silver and your gold are multiplied, and all that you have is multiplied; when your heart is lifted up, and you forget the Lord your God who brought you out of the land of Egypt, from the house of bondage; who led you through that great and terrible wilderness, in which were fiery serpents and scorpions and thirsty land where there was no water; who brought water for you out of the flinty rock; who fed you in the wilderness with manna, which your fathers did not know, that He might humble you and that He might test you, to do you good in the end— then you say in your heart, ‘My power and the might of my hand have gained me this wealth.’ “And you shall remember the Lord your God, for it is He who gives you power to get wealth, that He may establish His covenant which He swore to your fathers, as it is this day. Then it shall be, if you by any means forget the Lord your God, and follow other gods, and serve them and worship them, I testify against you this day that you shall surely perish. As the nations which the Lord destroys before you, so you shall perish, because you would not be obedient to the voice of the Lord your God.”
Deuteronomy 8:1-20 NKJV
This Law was a Tudor to lead them to Christ after Jesus came He instituted a New Covenant.
Therefore He who supplies the Spirit to you and works miracles among you, does He do it by the works of the law, or by the hearing of faith?— just as Abraham “believed God, and it was accounted to him for righteousness.” Therefore know that only those who are of faith are sons of Abraham. And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand, saying, “In you all the nations shall be blessed.” So then those who are of faith are blessed with believing Abraham. For as many as are of the works of the law are under the curse; for it is written, “Cursed is everyone who does not continue in all things which are written in the book of the law, to do them.” But that no one is justified by the law in the sight of God is evident, for “the just shall live by faith.” Yet the law is not of faith, but “the man who does them shall live by them.” Christ has redeemed us from the curse of the law, having become a curse for us (for it is written, “Cursed is everyone who hangs on a tree”), that the blessing of Abraham might come upon the Gentiles in Christ Jesus, that we might receive the promise of the Spirit through faith. Brethren, I speak in the manner of men: Though it is only a man’s covenant, yet if it is confirmed, no one annuls or adds to it. Now to Abraham and his Seed were the promises made. He does not say, “And to seeds,” as of many, but as of one, “And to your Seed,” who is Christ. And this I say, that the law, which was four hundred and thirty years later, cannot annul the covenant that was confirmed before by God in Christ, that it should make the promise of no effect. For if the inheritance is of the law, it is no longer of promise; but God gave it to Abraham by promise. What purpose then does the law serve? It was added because of transgressions, till the Seed should come to whom the promise was made; and it was appointed through angels by the hand of a mediator. Now a mediator does not mediate for one only, but God is one. Is the law then against the promises of God? Certainly not! For if there had been a law given which could have given life, truly righteousness would have been by the law. But the Scripture has confined all under sin, that the promise by faith in Jesus Christ might be given to those who believe. But before faith came, we were kept under guard by the law, kept for the faith which would afterward be revealed. Therefore the law was our tutor to bring us to Christ, that we might be justified by faith. But after faith has come, we are no longer under a tutor.”
Galatians 3:5-25