It may be helpful to look at other references to Satan in scripture: e.g. Ezekiel 28:11-19 God speaks of the king of Tyre and says: he was perfect, he was in the garden of God, Eden; he was the anointed guardian cherub, etc. Of course the king of Tyre was not in Eden and he was not the guardian cherub. Ezekiel is addressing Satan as the inspiration of the king. This passage is very important in understanding Job. God describes Job as the greatest man,'perfect', blameless, innocent (not sinless); same language that describes Satan in Ezekiel. In the book of Job, God is bringing together the two greatest created moral beings, Job and Satan, side by side, before an angelic audience and before mankind. God is indicting Satan for his iniquity, and He is proving His Righteousness and Character in Job's integrity. Satan inhabits Elophaz's dream in chapter 4 and inspires his arguments concerning self-righteousness and God's obligation to bless man. (God is worthy of man's blessing, not vice versa; thus God's disapproval) God rebukes the three friends in chapter 42 and restores them with Job's prayer and sin offering.
Similarly, in Isaiah 14 God addresses the spirit that inspires the king of Babylon. vs 12 ...How you have fallen from heaven, morning star, son of the dawn! You have been cast down to the earth, you who once laid low the nations! Also, Jesus addresses the spirit that inhabits Peter's good intentions in the garden Mt 16:23 ...get behind me Satan...; also the antagonist in the desert, Mt 4, is inspired by Satan.
Satan is not the snake in Genesis, or the king in Isaiah and Ezekiel, or Peter, rather he is the inspiration of iniquity and cursing of God. And Jesus teaches us to pray ...deliver us from the evil one... Mt 6:9 ff