The word Satan, in Hebrew, meant an adversary or opponent. The earliest reference using that word/name, is probably the Book of Job, (often held to be one of the oldest works in the bible), in which Satan is simply a member of God’s court, charged with testing humans for their fidelity to God. When God comments on Job’s blameless faith, Satan points out that since God has granted Job his every desire, Job has no reason to turn from God. God then grants Satan the power to remove all of Job’s family and possessions to see whether he will turn from God, which Job does not.
When the Septuagint, (the Greek translation of the Hebrew bible made in Egypt), was created between the third and second centuries B.C.E., the word satan was often translated to Greek as diabolus, or slanderer. I do not know what the beliefs of the Jewish diaspora in Egypt were that might have resulted in that translation.
In the various intertestamental works, (those Jewish and, later, early Christian writings), that influenced religious beliefs, but never made it into the scriptural canon of either the Jews or the Christians), the figure variously identified as Satan or the “diabolos” is depicted as a leader of rebelling angels who has his own powerful “kingdom” set up against God.
These intertestamental works provided much of the mythology that informed the early Christian comments about “the devil” (one translation of the Greek diabolos), hell, and related topics that are not found in either the Christian or Hebrew Scriptures. These works included several Books of Enoch, the Assumption of Moses, the Book of Jubilees, and others.
(Kanicbird’s claim about the sacrifice of Isaac comes from the Book of Jubilees, in which the demon Mastema, (meaning Hostility) plays the same role that Satan does in Job, persuading God to order the sacrifice as a test. In the Book of Jubilees, several acts from the Hebrew Scriptures in which God behaves violently are re-written to have Mastema either commit the act or persuade God to do so. While Mastema is a demon, (perhaps sired by a fallen angel on a human woman), he acts in accordance with God’s will in the way that Satan does throughout Hebrew Scripture. However, having taken the role of the “bad guy,” in later works his actions are attributed to evil.)
As Christian beliefs were written down and then expanded upon in commentaries, there was a certain amount of effort put into reconciling different passages and showing that separate metaphors referred to the same things. Following, not Hebrew Scriptures, but the intertestamental works, the letters of Paul refer to Satan on several occasions, not as God’s prosecutor, but as an enemy of God, and the 1st Letter of Peter refers to “the devil” (diabolos) in the same way. In Revelation, 12:9 and 20:2, the dragon is explicitly called the “devil” (diabolos) and Satan. Thus any references to anyone “testing,” serpentine, or deceitful were collected together to “mean” the same thing, thus bringing together the serpent in the Garden of Eden, the tester of Job, (since the Christians were using diabolos/slanderer from the Septuagint rather than Satan/opponent from the Hebrew Scriptures), the ruler of the fallen angels, and the ruler of Hell. Lucifer is simply the Latin word for “light bearer” and translates the phrase “son of the dawn” from Isaiah 14:12. When Christian writers began to collect all the various “bad” beings whom God would overthrow, Lucifer got picked up and tossed into the mix.