The “Sons of God” are the angels. Job 1:6, "…the sons of God came to present themselves before the LORD, and Satan came also among them." These angels were disobedient and chose to put on human bodies in order to enjoy the pleasures of living as human beings. They mated with beautiful women and produced the illegitimate, unauthorized offspring called Nephillim (Genesis 6:4). In Jude 6: it says: “And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.”
We see that God allowed sin not only to enter the world through the actions of Satan, but to be a source of temptation to the angels also. The angels became exposed to this peculiar temptation in connection with fallen mankind. We believe that Satan was involved in this experience.
Some of the angelic host gave in to this temptation, and some remained loyal to God. So we know that all the angels of Heaven were subjected to a great test of their obedience to their Creator. All those angels who are in harmony with God, according to the Bible, have stood their test. These, we understand the Scriptures to teach, have been granted the reward of everlasting life. They proved themselves faithful and obedient and demonstrated their loyalty to God. Those who fell were bound in chains of darkness unto the Judgment of the Great Day.