Let’s read Job 1:6-7, “Now there was a day when the sons of God came to present themselves before the LORD, and Satan also came among them. And the LORD said to Satan, ‘From where do you come?’ So Satan answered the LORD and said, ‘From going to and fro on the earth, and from walking back and forth on it’” (NKJV). I believe Satan was SUMMONED TO HEAVEN TO GIVE AN ACCOUNT of what he was doing. In other words, he was not “going in and out of heaven at will,” but was summoned by God to come into His presence and he had to obey that summons. So, even though he still has access into God’s presence, he can’t come and go whenever he wants to.

In your question you mentioned Satan being “the very embodiment of sin.” That begs the question, “Wouldn’t Satan’s presence, as a sinful being, bring defilement to heaven?” I don’t believe so. For one thing, Satan was NOT allowed to commit sin while he was in God’s presence. His presence there was completely controlled by God. There is a day coming when ALL SINNERS will stand in God’s presence. We read of this in Revelation 20:11-12, “Then I saw a great white throne and Him who sat on it, from whose face the earth and the heaven fled away. And there was found no place for them. And I saw the dead, small and great, STANDING BEFORE, and the books were opened. And another book was opened, which is the Book of Life. And the dead were judge according to their works, by the things which were written in the books.” This scene is describing the last final judgment when the Lord Jesus Christ summons ALL THE UNSAVED DEAD (the SAVED were resurrected one thousand years prior to this—see Revelation 20:4-6). They are there because they are commanded to come out of their graves to give an account of their lives (just as Satan was summoned to give an account of his actions in the day of Job). And we can be sure that there will be no open rebellion or any other acts of sin allowed when they do stand in Christ’s holy presence to be condemned for their rejection of Him and for all the sins they committed throughout their life.

Before we close, it would be good to remind ourselves that Satan’s limited and controlled access into God’s presence will soon end. We learn of this in Revelation 12:7-10, “And war broke out in heaven: Michael and his angels fought with the dragon; and the dragon and his angels fought, but they did not prevail,                NOR WAS A PLACE FOUND FOR THEM IN HEAVEN ANY LONGER. SO THE GREAT DRAGON WAS CAST OUT, that serpent of old, called the Devil and Satan, who deceives the whole world; HE WAS CAST TO THE EARTH, AND HIS ANGELS WERE CAST OUT WITH HIM. Then I heard a loud voice saying in heaven, ‘Now salvation, and strength, and the kingdom of God, and the power of Christ have come, for THE ACCUSER OF OUR BRETHREN, who accused them before our God day and night, HAS BEEN CAST DOWN.” If you read on in Job 1:9-11 you will see a clear example of Satan “accusing the brethren,” for he told God that Job only loved Him because he was blessed with material possessions. This has been Satan’s “chief occupation” when he is allowed into God’s presence, but the day is coming, as we have seen, when he will be expelled from the heavens permanently. You can also read Revelation 20:1-3 and 7-10 to see that Satan will also be cast into a bottomless pit for one thousand years and then into the lake of fire for eternity. (260.7) (DO)