Eternity
In many cases, the use of “eternity” in the Bible is pretty literal, simply meaning forever. This is especially true when the text refers to someone being condemned to hell or elevated to heaven. In some cases, however, “eternity” or “days of old” refers to what the Writings call the Most Ancient Church -- the first church among the earliest people, innocent souls who acted directly out of love of the Lord. Because of this association, things called “eternal” or “everlasting” usually represent the desire for good that arises from love to the Lord. If we love the Lord, then our desire will be to do His will and love as He loves. From that we will have a true desire to love and care for other people. That's the feeling described by “eternal.”
2 Corinthians 6:16
16
And what agreement hath the temple of God with idols? for ye are the temple of the living God; as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people.