When did Lucifer turn bad?

Answer 1

The Bible does not specifically state when the 'anointed cherub that covereth' happened, but it was before the renewal of the Earth and creation of man occurs in Genesis 1. Here is a Scripture commonly associated with the event:

Ezekiel 28:12-15

King James Version (KJV)

12 Son of man, take up a lamentation upon the king of Tyrus, and say unto him, Thus saith the Lord God; Thou sealest up the sum, full of wisdom, and perfect in beauty.

13 Thou hast been in Eden the garden of God; every precious stone was thy covering, the sardius, topaz, and the diamond, the beryl, the onyx, and the jasper, the sapphire, the emerald, and the carbuncle, and gold: the workmanship of thy tabrets and of thy pipes was prepared in thee in the day that thou wast created.

14 Thou art the anointed cherub that covereth; and I have set thee so: thou wast upon the holy mountain of God; thou hast walked up and down in the midst of the stones of fire.

15 Thou wast perfect in thy ways from the day that thou wast created, till iniquity was found in thee.