Explanation:
“Godlike shapes and forms
Excelling human, princely Dignities,
And powers that erst in Heaven sat on thrones;
Though of their names in Heavenly records now 

Be no memorial, blotted out and rased
By their rebellion from the Books of Life.”
(Lines 359-364)

Answer: This passage has been quoted from Milton’s ‘Paradise Lost’ Book-I, the angels though they were in a ruined state after the toil of war and the terrible degradation they had suffered from Heaven to hell, excelled human forms in appearance. Before their impious war against God, they were princely dignities who sat on the thrones of Heaven. As God’s obedient servants, they had their names written in the Book of Life.

But as a consequence of their foul revolt, they have forfeited divine grace and their names have been blotted out of Heaven’s good books.

The idea of obliterating the names of the fallen angels is suggested by Psalm ix: “Thou hast put out their names forever and their memorial has perished with them.”There is also a mention in Rev. iii 5: “He that overcometh evil, I will not blot out his name out of the Book of Life.”

Milton believes that the punishment inflicted on the rebel angels was well deserved by them. They had followed proud and ambitious Satan and fought the war in Heaven against the Almighty by abandoning the path of righteousness. And when they had fallen they did not repent but remained headstrong and submitted themselves to the rule of evil.