He is the spirit that is now working in the sons of disobedience. This is what describes the life of the typical unbeliever. It describes our life before Christ. We are not only described as dead, and disobedient, we are described as depraved . In verse 3 we read that we too all formerly lived in the lusts of our flesh.
Unsaved people live by their lusts .
This is not simply referring to sexual desires. Lusts refer to any selfish desires we may have. And we are described as people who live a lifestyle of indulging the desires of the flesh and of the mind. We were self-indulgent. And a self-indulgent person who is driven by his or her desires can be described as depraved.