For what our human nature wants is opposed to what the Spirit wants, and what the Spirit wants is opposed to what our human nature wants. Galatians 5:17
The Spirit and Human Nature are enemies, and this means you cannot do what you want to do. If the Spirit leads you, then you are not subject to the law. The Spirit directs your lives, and you will not satisfy the desires of the human nature.
The Gospel of John, chapter three spoke of the theme of rebirth; One has to be born again. The Spirit comes from we know not where and goes we know not where. This is what we might call Spirit. Only when we get in touch with the Spirit, mysterious and beyond human understanding, we are really reborn.
A new way of life in the Spirit which is leading and guiding us to face challenges, to resist temptations and to over come set backs. To set priority for Jesus and the Spiritual in our daily life.
Human nature is our nature subjects to the flesh. We use to do things that we do not want and do not do things that we want. We are always defeated by our flesh which leads to sin.
Cain and Abel were sons of Adam and Eve. The jealousy in Cain was so terrible, that he killed his younger brother. Blood brothers, just because God accepted the offering, which was more favorable; the first lamb born to one of his sheep Cain took the life of Abel, his younger brother.
This was human nature, controlled by the flesh, did a murder by Cain. His human desire was driven by his human nature as said in Galatians; we did the things which we did not want to do. And did not do the things which the Spirit wanted us to do.
We are too often focused on what we want, and miss the things that is important.