THE ANGELS THAT SINNED

2 Peter 2:4
For if God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved unto judgment;

The Apostle Peter used the term "the angels that sinned" in this particular verse in the New Testament and as a Bible student one must ask questions to come to conclusions about what he was referring to. 
Who were the angels that sinned? 
There must have been good angels in God's realm and there must have been bad angels. In answering these questions it will take several post.
When did these angels sin in reference to the timeline of the Bible?
TARTARUS
They were cast into hell. The Greek word Peter used in this passage is Tartarus which is the deep abyss that is used as a dungeon of torment and suffering for the wicked. It is the only time it is used in the New testament and is translated as hell by King James. In Greek mythology it is the prison for the Titans. It is far below Hades which is the lowest place on Earth. 
We can draw the conclusion that they were evil angels. God would chain them in prison in order that they couldn't hurt anyone anymore and that they reside in the darkest and lowest place in the Earth awaiting judgment. The purpose we put criminals in prison is so that they cannot hurt the population anymore.We see simply that they committed crimes and were sentenced and are in prison.

Matthew 25:41
Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:

We will see through these series of blogs that they will return to the Earth before the return of Jesus Christ. If you have never been taught this then hang on and we will in simplicity document the fact from the scriptures.