Summary: The angels were created by God as holy, honourable, and higher rank than human beings. They were created in perfect happiness and righteousness. The doubts and unbelief lead to a fall from the grace of God and eventually result in the destruction of the soul.

Jude 1:6 - Imprisoned Angels

Jude 1:6 “And the angels who did not keep their proper domain, but left their own abode, He has reserved in everlasting chains under darkness for the judgment of the great day.”

Domain of Angles:

The angels were created by God as holy, honourable, and higher rank than human beings. They were created in perfect happiness and righteousness. They were among the thrones, dominions, principalities, and powers. They beheld the face of God and enjoyed the presence of God. God assigned them a stipulated responsibility, a set place which was the earth.

The “demons” or “devils” are angels who decided to follow Satan and defy God. Satan rebelled against God (Isaiah 14:12-17; Ezekiel 28:11-19), and some of the angels too joined him. They are the satanic army of evil spirits (Matthew 25:41; Revelation 12:9), and they are also called “stars of heaven,” (Revelation 12:4).

Chains of Darkness:

They mounted an attack against God in heaven. They were defeated and cast down and imprisoned (Revelation 12:3-4,9; 2 Peter 2:4). God punished these spiritual beings as under trials. He chained them in a place of darkness waiting for a sentence (2 Peter 2:4, Revelation 20:7–10). It may denote the place and state where they are, either in the darkness of the air, in the dark parts of the earth, or in hell. They are under the power of sin, which is darkness, and without the light of God's countenance, or any spiritual knowledge, or comfort of God. They are under house arrest.

Judgment of the great day:

It is fixed by God unknown to men and angels. The Judge will appear in great glory. The dead will be raised, and all nations will be gathered together, and the process will be with great solemnity; the thrones will be set, the books opened, the several sentences pronounced. (Revelation 20:11-15, Joel 2:31). They will eventually be thrown into, and destroyed in, the Lake of Fire.

Sin of Dissatisfaction:

The reference to the disobedient, and dissatisfactory angels over their positions and authority refers to Satan and his comrades (Isaiah 14:12–21; Ezekiel 28:12–19). Almost one-third of God’s creation of the Angels fell from their position. The doubts and unbelief shall lead to a fall from the grace of God and eventually result in deliberate rebellion against God, leading to the destruction of the soul. Their discontent caused them to attempt to take by force what had not been given as of Korah's rebellion (Numbers 16:1-35). They did not stay in their natural spiritual domain, the spiritual world, but came into the physical world. They also left their natural spirit bodies (their “proper dwelling”) came into concretion and lived in the physical world, taking human females as wives and corrupting the physical world of humans.

Some interpreters try to explain the existence of the giants in the prehistorical period mentioned in Genesis connecting with these fallen angels. They took on a human form in order to have sex with human women, which resulted in a hybrid offspring, described in Genesis as giants or Nephilim. The rabbis taught that; it is spoken about in the book of Enoch, and even the Jewish historian Josephus writes about it in his Antiquities of the Jews.

But I differ from that understanding because Genesis 6:1-4 says that they were the Sons of God. But Angles never became the Sons of God (the word Angels in Job 38:7 refers to Sons of God in Hebrew), in fact, they are the ministering spirits of God as per Hebrews 1:14. Also in Hebrews 2:16 we read that it was not angels but the descendants of Abraham that Jesus came to help.

(Ref: Bibleref.com; Bible study tools; knowing-jesus.com; Revised English Version; Biblehub.com; Study light)