"At that time I said to you, 'You are too heavy a burden for me to carry alone. The Lord your God has increased your numbers so that today you are as numerous as the stars in the sky. May the Lord, the god of your ancestors, increase you a thousand times and bless you as he has promised! But how can I bear your problems and your burdens and your disputes all by myself? Choose some wise, understanding and respected men from each of your tribes, and I will set them over you.'" NIV translation
Moses recounts his first mistake of the journey in the fact that he had let advice of men supercede the call of God on his life. He had appointed leaders over Israel even though God was with them and he was to take the problems to God on their behalf. These leaders would become the basis for the Jewish rulers (the Sanhedrin) which would arrest Jesus Christ.
"You answered me, 'What you propose to do is good.' So I took the leading men of your tribes, wise and respected men, and appointed them to have authority over you - as commanders of thousands, of hundreds, of fifties and of tens and as tribal officials. And I charged your judges at that time, 'Hear the disputes between your people and judge fairly, whether the case is between two Israelites or between an Israelite and a foreigner residing among you. Do not show partiality in judging; hear both small and great alike. Do not be afraid of anyone, for judgment belongs to God. Bring me any case too hard for you, and I will hear it.' And at that time I told you everything you were to do." NIV translation
Moses reminds the people of the fact that he had bowed to their desire for leaders and he had instructed them. This might all seem good but we must remember that Israel was to be different. They were to be led by God Himself and not by a governing body like other nations. The effects of this mistake linger to this day and will continue until Jesus returns for the Millennial Reign.