He gave the whole message, every part of the message, everything the Lord commanded. He kept nothing from the elders, representatives of the people. We must be faithful messengers and channels of what the Lord commands us to say, when it comes to sharing the Word.
Exodus 19:8 "... All that the Lord has spoken we will do ..."
Resolutions of the flesh inevitably fail - what the Lord has spoken needs His grace and power to be fulfilled. It is only the regenerated, renewed, spirit indwelt, filled, that can please the Lord.
Romans 8:8-9 "So then, those who are in the flesh cannot please God. But you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. Now if anyone does not have the Spirit of Christ, he is not His."
The New Testament teaches man's inner incapability, pointing man to Christ who alone can save and keep him, and give him by the Spirit, victory over the flesh. (Galatians 3:24-25 ).
Romans 8:3-4 "For what the law could not do in that it was weak through the flesh, God did by sending His own Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh, that the righteous requirements of the law might be fulfilled in us who do not walk according to the flesh but according to the Spirit."
Romans 10:4 "For Christ is the end of the law for righteousness to everyone who believes."
The mediator, Moses, returned the peoples' words to the Lord (Exodus 19:8 ). God heard what the people said. He knew what was in their hearts. Moses coming with their words demonstrated that there was a barrier between the holy Lord and the sinful people, that could be bridged by a mediator. Pointing to Christ the only one Mediator between God and men. (1 Timothy 2:5 ).

Do you believe that resolutions of the flesh inevitably fail?