How you have fallen from heaven, morning star, son of the dawn! You have been cut down to the earth, You who have weakened the nations.
– Isaiah 14:12
I, Jesus, have sent my angel to give you this testimony for the churches. I am the Root and the Offspring of David, and the bright Morning Star.
– Revelation 22:16
This is one of the first tricky/wacky Biblical translations I discovered when I first started reading the Bible critically back in 2000. Many conservative Christians say that Isaiah 14:12 is talking about a being that the Jews thought was called Lucifer. But the actual translation of the Hebrew would be “day star” (helel). How did this happen? Well, back when Jerome translated the Hebrew Tanakh into Latin around 400 CE, he used his vernacular Latin to describe the “day star” of the Hebrew. At the time, the commonly known Day Star (or Morning Star) wasn’t called Venus, it was called Lucifer.
Lucifer comes from the Latin “lucem fer” which means light bringer. The lucem fer was a herald for the sun in Latin, thus a “morning star”. We now call this morning star Venus. In actuality, this passage of Isaiah is talking about a Babylonian king who persecuted the Jews. The title “day star” given because he wore a lot of exuberant jewelry, much like how Louis XIV got the title “Sun King”. This chapter of Isaiah is part of a larger taunt song against this Babylonian king. In the LXX version of Isaiah, “helel” is rendered as εωσφόρος (eosforos [or ewsforos]), and the rest of the passage reads “ο πρωι” which would be “[of] the morning” in Greek. Εωσφορος is a proper name which comes from φωσφορος (phosphoros) which literally means φως (light) φέρω (I bring) – light bringer. Thus the passage in Greek is faithful to the Hebrew – light bringer of the morning.
Isaiah promises that the Israelites will be freed and will then be able to use in a taunting song against their oppressor the image of the Morning Star, which rises at dawn as the brightest of the stars, outshining Jupiter and Saturn, but lasting only until the sun appears. This image was used in an old popular Canaanite story that the Morning Star tried to rise high above the clouds and establish himself on the mountain where the gods assembled, in the far north, but was cast down into the underworld. […] As the Latin poets personified the Morning Star and the Dawn (Aurora), as well as the Sun and the Moon and other heavenly bodies, so in Canaanite mythology Morning Star and Dawn were pictured as two deities, the former being the son of the latter.
Unfortunately (or humerously), Jesus apparently uses the same title for himself in Revelation 22:16 – “[bright] star of the morning” (αστήρ ο πρωίον). 2 Peter 1:19 also uses the phrase “morning star” but uses the one closer to the LXX version of Isaiah – φωσφορος, which is literally light bringer. Each case it is understood to mean the morning star.
Satan falling from heaven is strictly Christian theology, Judaism has no concept of a fallen, rebellious angel. This is due to this misunderstanding and conflation of Hebrew culture and language, Greek, and Latin culture and language. Quite literally lost in translation. But if you want to get overly literal, you could say that Jesus himself is Lucifer. You would technically be right according to the literal translation of the Latin “Lucifer” and Revelation 22:16 / 2 Peter 1:19.