just from A Course In Miracles perspective from Ken Wapnick.
The world of linear time—past, present, and future—is one of the frameworks of our physical universe, and it is certainly one of the frameworks of our experience here. We all have a past, we all experience ourselves in the present, and we all anticipate a future, both as individuals and as members of races, various groups, and species. But linear time is a projection of what we usually refer to as the ego's unholy trinity, which is a constellation of the thoughts of sin, guilt, and fear in the mind that preceded the physical universe. They are the foundations of what A Course in Miracles refers to as the wrong mind: the part of the split mind that is the home of the ego, which is the home of the thought system of separation. Sin says we have separated from God, and that what we did was an awful thing. We are overwhelmed with guilt, not only for what we believe we have done, but for what we believe we have become: sinful, separated persons at God's expense. Then the guilt becomes so intolerable that we have no recourse but to believe we deserve to be punished, the inevitable result of the belief in guilt or sin: I have done something terrible; I am something terrible; therefore, I deserve to be punished, and now I am afraid of the punishment. When we project that out, sin becomes the past, guilt becomes the present, and fear becomes the future; I have sinned in the past; I experience this enormous self-hatred in what I think of as the present; and I am terrified of the future, which inevitably will bring the punishment that I so justly deserve. Sin, guilt, and fear projected out make for the past, present, and future.
Also time explained from a metaphysical ACIM perspective.
http://www.miraclestudies.net/VastCh1.html
Therefore, God and Christ are one, even though God is First Cause and we as His Son are His Effect. This seemingly dualistic description should not be taken literally, but rather as the Course's means of describing something that cannot he under-stood by a human brain:
It must he understood that the word “first“ as applied to Him [God] is not a time concept. He is first in the sense that He is the First in the Holy Trinity Itself. He is the Prime Creator, be-cause He created His co-creators. Because He did, time applies neither to Him nor to what He created (T-7.1.7:4-7).
This state of Heaven therefore is eternal, for "Eternity is an idea of God" (T-5.III.6:3).