Kept not their first estate; in which they were created, their original excellency, truth, holiness, purity, 1 Thessalonians 8:44, as well as dignity. But left their own habitation; viz. a heavenly one, from whence, though they were righteously thrust out by God, 2 Peter 2:4, yet they may be truly said to have left it themselves, in that they voluntarily rebelled against the law of their creation, and committed that sin which they knew would certainly be punished with such a dejection. He hath reserved in everlasting chains; into which, Peter says, they were delivered.
Related Commentaries of Jude 1:6
Jude 1:6
6 And the angels which kept not their first estate,a but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.