Darkness does exist in Heaven and there was no sin before Satan,
Rev 22:5 And there shall be no night there; and they need no candle, neither light of the sun; for the Lord God giveth them light: and they shall reign for ever and ever
First, where do you see "darkness in Heaven" in this passage?
Secondly, this is referring to the new heavens and Earth. Not the one in existence now.
When this new heavens and earth are created...all demons will be in Hell (gehenna).
Yet they were expelled into darkness when they sinned
Jude
1:6
And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.
No, LoDebar, this is specific to the Angels which kept not their first estate. It does not apply to Satan and all demons, because he and they are still active on this earth. He is called "the god of this world." He walks about as a roaring lion seeking whom he may devour.
Darkness was created to hold the angels. There was no need before.
So give me Scripture for that. Show me where the statement "Darkness was created to hold the angels" can be found.
Hell was created for Satan and his angels:
Matthew 25:41
King James Version (KJV)
41 Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:
Demons know that their judgment is pending...
Matthew 8:29
King James Version (KJV)
29 And, behold, they cried out, saying, What have we to do with thee, Jesus, thou Son of God? art thou come hither to torment us before the time?
The implication being...it hasn't happened yet.
Jesus ministry was to those bound as prisoner in darkness
Isa 42:7
To open the blind eyes, to bring out the prisoners from the prison,
and them that sit in darkness out of the prisonhouse.
And the darkness they sat under wasn't being on the earth, it was being under sin.
That is what Christ came to remedy.
And as I showed you before, Christ's ministry was specific to Israel...not the world. He did not reveal the Mystery of the Gospel of Christ to His Disciples, the Comforter did that when He came.
And I would suggest to you that in view is the prison house of Hades, from whence Christ liberated those held captive by sin.
Again, men did not go into the presence of God until Christ died for them:
Hebrews 9:6-9
King James Version (KJV)
6 Now when these things were thus ordained, the priests went always into the first tabernacle, accomplishing the service of God.
7 But into the second went the high priest alone once every year, not without blood, which he offered for himself, and for the errors of the people:
8 The Holy Ghost this signifying, that the way into the holiest of all was not yet made manifest, while as the first tabernacle was yet standing:
9 Which was a figure for the time then present, in which were offered both gifts and sacrifices, that could not make him that did the service perfect, as pertaining to the conscience;
In view is man's entrance to God, which was accomplished in parable, not in reality. Men only had entrance to God's presence on this earth, not in His Realm, Heaven. The "Holiest of All" is defined as Heaven here:
23 It was therefore necessary that the patterns of things in the heavens should be purified with these; but the heavenly things themselves with better sacrifices than these.
24 For Christ is not entered into the holy places made with hands, which are the figures of the true; but into heaven itself, now to appear in the presence of God for us:
We see how we enter into God's presence now that the way is made manifest:
Hebrews 10:19-20
King James Version (KJV)
19 Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus,
20 By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh;
"The Blood" and "His flesh" speak of His death in our stead.
And we go back to what Adam lost...entrance to the presence of God, and thus communion with Him.
Christ remedied that condition for man, for God was in Christ reconciling the world unto Himself. And in the Greek, the word translated reconciliation is also translated Atonement.
God bless.