In Job, we have the earliest mention (historically speaking) of Satan by name. Not even in Genesis is he mentioned by name-and the time of Job was early in history, for he was the son of Issachar, the son of Jacob (Genesis 46:13). It is clear in Genesis 3 that there was an invisible enemy who caused the fall of man, but in the passage he is shown using the serpent as a tool, the same way that he used Peter (Matthew 16:23). In Job 41 he is symbolized by a great dragon. He is the evil spirit working in the children of disobedience throughout the ages (Ephes. 2:1-3). Here he is named and spoken of as a real person and shown to have access to heaven with power to accuse the brethren and seek their destruction (Rev. 12:9-12). The word Satan means adversary. See note, 1 Kings 11:14, and The Doctrine of Satan.
Finis J. Dake, Dake Topical Index, WORDsearch CROSS e-book, Under: “Satan, First Mention of”.