Paul, in a curious passage while chastising the "saints" (ie; believers) in Corinth for taking their issues w/ one another to local non-believing judges says this:

"Dare any of you, having a matter against another, go to law before the unjust, and not before the saints?
Do ye not know that the saints shall judge the world? and if the world shall be judged by you, are ye unworthy to judge the smallest matters?
Know ye not that we shall judge angels? how much more things that pertain to this life?" 1Cor6:1-3

Noting the 2nd and 3rd verses this entire episode, the Great Controversy between Lucifer and Jesus that has transpired across the entirety of earth history, will be finally assessed and judged during the 1000 years the overcoming believers in Jesus will spend in heaven, in the Father's house of many mansions; we will be the jury that will judge whether God's judgement on the wicked, that includes the fallen angels, is true and righteous.