The word Satan figures in the Hebrew Bible, but not as a proper name. As a noun it denotes an adversary; as a denominative verb, to oppose or obstruct or be hostile.
It is sometimes used in a human sense; in Psalm 109:6, for instance, it suggests the counsel for the prosecution in a court of law.
It does not begin to have a superhuman sense until late in the Biblical period; in Zechariah 3 and the Book of Job it is applied to the prosecutor in the heavenly court.
But even in this sense, Satan is not a demon. At best, he is one of the celestial beings, but it may be that the word is merely a colourful metaphor and does not imply that there is any actual being with that name.
Nor is Satan opposed to God. At worst, he is simply a devil’s advocate drawing God’s attention to things that appear to be wrong.
Kaufmann Kohler’s theory, in his “Jewish Theology”, chapter 31, is that just as the serpent in the creation story “represents the evil inclination which arises in man with his first consciousness of freedom”, so Satan is an allegorical figure “representing the evil of the world, both physical and moral”.
In post-Biblical Jewish sources there are very few references to Satan, and those that are found have no dogmatic or authoritative significance. Satan continues to represent the impersonal force of evil; thus, the Tosefta Shabbat advises that one should “not go on a journey with a wicked man, because Satan accompanies him”.
In Jewish liturgy the few references to Satan are all impersonal, for instance the evening prayer that God may remove the adversary “from before us and behind us”, and the morning prayer for protection from “the destroying adversary”.
Popular lore has a far stronger notion of Satan deriving from the New Testament. There he not only personifies the spirit of evil but assumes an independent personality hostile to Jesus and to God.
As a result, Milton, writing in an age when people regarded Satan as the presiding demon in stark opposition to God, was able, at least in the first two or three books of “Paradise Lost”, to draw a sympathetic picture of Satan and turn him into almost an epic hero.
For Judaism, all this goes much too far.
WHAT’S SO SPECIAL ABOUT CHASSIDUT?
Q. What was so special about the Chassidim?
A. The Divrei Chassidim says, “Wisdom was limited to the erudite few until the Baal Shem came and revealed the Lord to all men and showed how to cleave to Him even in our ordinary actions”.
Abraham Joshua Heschel commented, “Many Jews talked about God, but it was the Baal Shem Tov and his followers who brought God to the people. This is perhaps the best answer to the question of how to explain the unbelievable impact these men had in such a short span of time”.