Satan was in Heaven during the Old Testament. He was a council to God the father. Satan, had originally been called Lucifer, the morning star. He had a symbolic connection to consciousness and creative change. Lucifer evolved into Satan. As Satan he became the CEO in charge of humans. This position was granted at the time Adam and Eve, who ate of the Tree of Knowledge. He was the serpent in the tree and had demonstrated he had a way with humans.
In Revelations, there is a war in Heaven and Satan is thrown from heaven. This begins a new age, where Satan is no linger the CEO of humans, as had been sanctified by God. Now he becomes the Devil. The Devil is more free lance.
Because Satan is thrown from Heaven to the earth, it becomes unclear to the humans, whether anything has changed. The same spiritual principle; Satan, is still in action on earth, but now, not in any official capacity. However, this change of divine priority, is not yet clear to the humans.
It is like having a CEO who has been fired by the board of directors. But this firing has not yet been announced publicly, since he gets to finish his contract. Those in power, below him, still want to serve him, not knowing he no longer works for the company. Instead, he is secretly working for himself. He is trying to steer the ship way from the original goal of the Old Testament, toward a new place where he can regain full control. This leads to the Anti-Christ and False Prophet and the Abomination of Desolation.
The first Messiah or Jesus comes while Satan is sanctioned by God as CEO. Satan had more self control and plays his role as the CEO in God's drama. The second coming of the Messiah, occurs after Satan has gone renegade, and has brought the world to the brink of total war and destruction. The New Messiah is the new CEO called faithful and true to God.
The Saints begin to notice the distinction between Satan in Heaven and Satan gone renegade, very early. They see the signs of change. They try to help others make the right choices. However, the majority cannot make this distinction, but still believe in changes being made, in times and laws, is a continuing part of the Old Testament dispensation.
After all the Saints are sacrificed, the end comes. The second coming is an awakening where all start to see, and order is restored.