Eternity is a concept that's hard to grasp. It's a little easier if we try to grasp the difference between "forever" and "forever and ever".
The the following two verses:
Ecc 1:4 ... the earth abideth forever.
Isaiah 24:20 ... the earth shall fall and not rise again.
So "forever" means as long as the earth lasts.
That does not make it illogical. There is a well-developed perfectly logical mathematics of infinity (in fact, of an infinity of infinities!)
Concepts like these boggle the imagination, and highlight the finiteness of the human mind.
The Bible tells us that there "was" an Eternity Past before the worlds were made. In this Eternity, nothing existed except God. "In the beginning, God ..." Genesis 1:1a.
We are now in Eternity Present, in which God has created worlds, and populated them with angels, a variety of non-living objects, and living beings, and in which he placed humankind. This provides all the Time needed for the flow of history through the Dispensations in which God deals with humankind in different ways from the Dispensation of Innocence to the Dispensation of the Kingdom.
But we must remember that from God's perspective, the whole of Eternity is Eternity Present.
Time is an interesting concept. God is not in time as we are in time. Our Father has access to every moment in our lives from beginning to end as though they were the present. By the Holy Spirit, we can actually access those times in our pasts when we felt abandoned, abused, betrayed, fearful, happy, fulfilled, or any other emotion or condition. Not only can the believer be forgiven for the past, he/she can also travel back in time with God, see Him as "a very present help" in the past, and redeem those past times that the enemy wanted to use for evil.
From His Eternal Perspective, God can and does Step Into Time
Imagine for a moment that all of eternity is represented by a large piece of paper. This is where God is: unlimited by time and space. Now draw a line on that piece of paper that represents time with a beginning and an end. This line begins when God instituted time at creation, and it will end when God says, "Time shall be no longer" (Revelation 10:6). Man lives on the line, while God can step in and out of time according to His purposes and plans. God sees all of time at once and doesn't have to wait for anything to happen; all is present for Him. This is a simplified explanation of a complex idea, but it works.
We, however, must learn to respond to Him within time. We are called to represent Him as ambassadors in our generation. The decisions and actions we take now affect three generations ahead. Therefore, when we know how the Lord wants us to respond and we do so, His glory infiltrates the earth and we see Him change our atmosphere and environment. Because of God's position relative to time, He can--and often does--seem to answer our prayers before they have been uttered!
God has chosen us as the necessary link to bring His will from Heaven to earth. He wants us to commune with Him, listen carefully to His voice, gain prophetic revelation, and decree that revelation into the earth. This will unlock miracles and release His blessings. Once we hear God, we can intercede. We can also prophesy. Prophecy is declaring His mind and His heart. When we receive prophetic revelation, we need to decree the prophetic revelation and then the atmosphere into which we decree goes on "Heaven's time" instead of "earth time."
Finally, redeemed mankind goes into Eternity Future (with the Father, Son and Holy Spirit, Three Persons who are One God), and with the Angels of God. Very many human beings are in the collective Bride of Messiah, others are Old Testament saints and Tribulation martyrs who are "Friends of the Bridegroom". These do not marry nor are given in marriage but are like the angels. These live in the New Heavens. At the same time, on the New Earth, are the righteous to whom Messiah said "Possess the Kingdom prepared for you from the foundation of the earth." These earthly citizens of Eternity will beget new citizens of the Kingdom, and because there will be no death, the increase in population will be quite rapid. Of these it is true that "of the increase of His Kingdom there will be no end." (Isaiah 9:6. Luke 1:33). Eventually, the population will outstrip the capacity of planet Earth, and God will lift the quarantine He has imposed on humankind (which restricts him to earth so that he cannot proceed to ravage and pollute God's universe). With the quarantine lifted, men and women will at last spread beyond the confines of the solar system. At last the vast reaches of the universe will be accessible to us. We can only wonder at the exceeding lavishness of God's gift toward us.
Those who died without Christ will spend Eternity Future in eternal darkness (Rev 20:15)
The concept of Eternity was well and truly grasped by Arthur Stace, who came to be known as the Graffiti PreacherTHE TRUE FASCINATING AND CHALLENGING STORY OF ARTHUR STACE, GRAFFITI PREACHER