We wrestle every day against the sinful influences of this world. They bombard us everyday in every way. Our sinful or self nature does not have the capacity in and of it self to combat these influences thus our spirit has to fight against the works of the flesh. The works of the flesh are sinful qualities which contrast the fruit of the Holy Spirit.
For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. 1 John 2:16
The Bible warns that the drunkard will be poor: