Q. In the opening part of the book of Job, how can a totally evil being like Satan be allowed to enter directly into the presence of God? I’ve always been told that God is so holy that He can’t tolerate any evil in his presence.
To state the matter simply, the character in the book of Job commonly called Satan in English translations isn’t exactly the same as the devil or Satan described in the New Testament.
As I explain in my Job study guide, in this opening narrative, “Satan” is not actually a name. The Hebrew word satan literally means “adversary,” and in the book of Job it’s always preceded by the word “the,” so this is actually a title: “The Adversary.” (Many Bibles, the ESV and NRSV for example, have footnotes explaining that the Hebrew actually reads “the Accuser or the Adversary”; others like the NIV explain the meaning of the term: “Hebrew satan means adversary.”)
The word satan is used many times in the Old Testament to describe a determined and persistent opponent, as in the account of Solomon’s reign in Samuel-Kings: “Rezon son of Eliada . . . was Israel’s adversary as long as Solomon lived.” As a noun, the root satan is used in a specialized way to describe the accuser in a legal proceeding; as a verb, it describes the act of accusing, as in Psalm 38: “My enemies . . . lodge accusations against me.” Here in the book of Job, the Adversary is both a determined opponent of God and an accuser of anyone who seeks to follow God faithfully.
While this character is similar to the devil or Satan described in the New Testament, the portrait isn’t drawn as fully in the book of Job. The book doesn’t account for where he came from or how he became opposed to God. It does portray him as a crafty and malicious player within the complex moral web of the universe, but not necessarily as a consummately evil being who could never be allowed into the presence of a holy God.

I am still left wondering why this “adversary” is permitted in the presence of God, when I cannot be in the presence of God without being washed clean by the saving grace granted through my faith in Jesus.
I think the difference is between being in the presence of God in loving fellowship, for which we need saving and cleansing grace through faith in Jesus, and being in the presence of God for some other purpose. On the day of judgment, everyone will stand in the presence of God, but not everyone will be there in loving fellowship.