Quantrill,
I never said God's work was inadequate... I'm saying God gives choices and those that believe will do what He says and those that do not will not serve Him. Israel would not do God will because they chose not to believe Him. Scripture teaches Israel hardened their heart to God and His law.
Deuteronomy 32:20
And God said, I will hide my face from them, I will see what their end shall be: for they are a very froward generation, children in whom is no faith.
Deuteronomy 32:21
They have moved me to jealousy with that which is not God; they have provoked me to anger with their vanities: and I will move them to jealousy with those which are not a people;
I will provoke them to anger with a foolish nation.
God punished Israel because they would not believe in obedience to His word. Israel was stiff-necked against God and would not obey Him.
Hebrews 3:10
Wherefore I was grieved with that generation, and said, They do alway err in their heart; and they have not known my ways.
Exodus 32:9
And the Lord said unto Moses, I have seen this people, and, behold, it is a stiffnecked people:
Plenty scripture teach Israel would not keep the law; not that they could not rep the law.