"O Jerusalem, Jerusalem, thou that killest the prophets, and stonest them which are sent unto thee, how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not!" Matt 23:37 (emphasis mine).
Ye would not! This is the fundamental problem with humanity. We do not want help from anybody, not even the loving God who created us for His glory. We want be self-sufficient. Like a child, we say "I do it mine self," and stubbornly refuse to listen to our divine Parent. And He grieves because He wants us in relationship with Him.
This unwillingness to obey God's command is the same problem that got us into trouble in the first place.
The devil in the form of a serpent told Eve that God was holding out on her and Adam, keeping the knowledge of good and evil to Himself, so that they would stay under His control. Then our first parents decided that that would not do--they wanted to have the knowledge, instead of trusting the One who personally breathed Life into them to do His Will. So they ate of the Fruit and condemned the entire human race to sin.
The universe's problems occurred because of humanity's will. We would not do as God asked, and we lost Eden, our chance to walk with God in the Garden, and, ultimately, immortality on the first Earth. Now we can only attain these things through the death of His Son. We must deny our old nature, our will, pick up our crosses, and follow Him (Matt 16:24) in His Holy WILL.
In fact, our old will must be killed, crucified with Christ, so that we will not to do evil, our will, but God's. We cannot just "fix" the old will; it is broken beyond repair. We need a new will and there is only one way to get it. Through Christ. And anyone who is truly in Christ will have a new will--His.
Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin. Romans 6:6
Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
2Cor. 5:17
For it is God which worketh in you both to will and to do of his good pleasure. Philipians 2:13
However, despite being reborn, we find ourselves still trapped by our old nature. Like the Old Man of the Sea (Arabian Nights), this old nature gets us in a strangle hold and will not let us go, making us carry him this way and that wherever he wills, and punishing us when we try to get away. However, unlike Sinbad we cannot be rid of our Old Man by getting him drunk. We are stuck with the Old Man. But believers are regenerated as new men through the death and resurrection of Christ, so why, if we are reborn spiritually as new men and women and have a new will, the Will of God, why do we still sin? Paul gives an explanation regarding the law which also applies in this case(the Law being the Ten Commandments, God's holy will):
Romans 7:14-23
The Old Man still has us in his strangle grip, and no matter how hard we try to get away, we cannot. Even though we will to do God's will, we are hampered by the flesh. Christ has died and risen and redeemed us, but until we "shuffle off this mortal coil," we can never be completely free of our sinful nature. Even though the thing is done, as Christ said on the cross "It is finished," we are still constrained by the body.
The believer can say along with Paul,
O wretched man that I am! who shall deliver me from the body of this death? I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin.
Romans 7: 24-25(emphasis mine)
As the redeemed of Christ, we are already free of the law of sin, even though we still feel its effects.