In the Old Testament, Satan is a common noun, as a fallen creation of God, as a rebellious subject of the power of God, who, against his own will, can ultimately contribute to the fulfillment of God's plan[9]. In the Bible, this word refers to people[10][11]. The exception is probably the book of Chronicles[12][13].

With regard to the angel, the very first mention in the Bible appears in the book of Numbers[14], where the word is used in the direct meaning of “hindering”[15].

As the name of a certain angel, Satan first appears in the book of Zechariah[16], where Satan is the accuser at the heavenly court.

According to Christian tradition, Satan first appears on the pages of the Bible in the book of Genesis in the form of a serpent, who seduced Eve with the temptation to eat the forbidden fruit from the Tree of the Knowledge of Good and Evil, as a result of which Eve and Adam sinned with pride and were expelled from paradise, and doomed to earn their bread in sweat of the face with hard work[17]. As part of God's punishment for this, all ordinary snakes are forced to "walk on their belly" and feed on "the dust of the ground"[18].

The Bible also describes Satan as Leviathan[19]. Here he is a huge sea creature or a flying dragon[20][21].

In a number of books of the Old Testament, Satan is called an angel who tests the faith of the righteous[22]. In the book of Job, Satan questions Job's righteousness and invites the Lord to test him. Satan is clearly subordinate to God and is one of his servants (bnei Ha-Elohim - "sons of God", in the ancient Greek version - angels)[23] and cannot act without his permission. He can lead the peoples and bring down fire on the Earth[24], as well as influence atmospheric phenomena[25], send diseases[26].

In the Christian tradition, Isaiah's prophecy about the king of Babylon is attributed to Satan[27]. He was created as an angel, but having become proud and desiring to be equal to God[28], he was cast down to earth, becoming after the fall the "prince of darkness", the father of lies, a murderer[29] - the leader of a rebellion against God. From the prophecy of Isaiah[30] the "angelic" name of Satan is taken - הילל, translated as "luminiferous" (lat. Lucifer)[31]. Many theologians (despite the fact that the word of the Lord for Ezekiel was addressed to the king of Tyre[32]) refer to Satan also a passage from the Book of the Prophet Ezekiel[33]: