The BITTER MEMORY is of his former glory. The place Satan was banished from was a lot like Eden, and Satan is doomed to pine for Heaven for the rest of his days. The memory of his once being happy is unbearable for him. He is fiercely jealous of Adam and Eve and the love that they shower on one another and that they are given by God.
What he WAS was an angel. What he IS is the torturous Hell he has become for himself. He knows that this suffering must only increase. The WAS, IS, MUST BE sequence calls to mind the popular prayer "Glory Be", where is spoken, " As it was in the beginning, is now, and ever shall be " This brings an element of providence into the poem. The big-picture mentality comes into play. All of these things must happen so that Christ can come down to Earth and redeem mankind, therefore reaping the greater glory for God. Satan has this knowledge and wants to give it to Adam and Eve so he will not be alone in his suffering. It is a "misery loves company" type of situation. Later in the poem, Satan expresses great admiration for the humans; his real dispute is with God, not them.
Lisa Stanton loyaltotheroyal@hotmail.com