Jewish Sources On "HaSatan" or "The Adversary", or "The Devil"

BecomingJewish.org:


Satan

Satan, or more properly, HaSatan is an angel who resides in the heavenly realm. HaSatan means the accuser or the adversary. The term Satan or HaSatan is used in three different contexts within the Tanach.^[1]

First, as an enemy in war as seen in I Kings 5:18: And now the Lord my God has given me rest on every side, (there is) neither adversary (שָׂטָן) nor evil occurrence.^[2]

Second, as an accuser before the seat of judgment as seen in Psalm 109:6: Set a wicked man over him, and let an adversary (וְשָׂטָן) stand at his right hand.^[2]

Third, as an adversary in the general sense of the term as seen in II Samuel 19:23...

HaSatan is an angel who watches over the activities of humanity, searching for mankind’s sins and then appearing as their accuser to Hashem. HaSatan is not considered an opponent to Hashem as Christianity teaches. Monotheistic teachings are no more disturbed by the existence of HaSatan than by the presence of other beings that go before Hashem. This view is shown in Zechariah 3:1-2 where HaSatan is described as the adversary of the high priest Joshua....

Head Coverings By Devorah:

Ha-satan is Identified with the Yetzer Ra:

In Judaism, ha-satan (the adversary) is mostly identified with the yetzer ra, but also identified with one who leads astray, then brings accusations against man.  Its chief functions is those of temptation, accusation and punishment.  Under the control of G-d it acts solely with divine permission to carry out its deeds.

As we see in the book of Iyov, ha-satan's function is described as that of testing the sincerity of men's characters.  Ha-satan is at all times under the control of G-d and keeps within the limits which G-d has fixed for it.

In Talmudic literature, ha-satan's function is to strengthen man's moral sense by lending him into temptation....  

Orthodox Judaism: Purpose of HaSatan:

Firstly, "the Devil" and "Satan" are one and the same - I think this nomenclature is used interchangeably rather than to show they are different entities.  

Satan is indeed G-d's angel (messenger) sent with the explicit purpose of making us the best we can be - challenging us to do the right thing by presenting a not-so-clear choice.  Remember Deuteronomy 30 - choose between life and good, or death and evil - and we are perfectly capable of making the right choice.  Satan is sent to not throw you off the righteous path, but to help you walk it in a more confident way.  

Hashem gives us all our challenges in order for us to overcome them and become stronger. Only in adversity do we grow; otherwise, we would not advance at all.  It doesn't mean Hashem sends Satan to drive you into evil; He sends Satan so you could choose good and therefore become more like Hashem.  

The statement you quoted correctly states that evil is created only by the absence of good.  Speaking in more spiritual terms, G-d is the ultimate good, and everything is G-d, so evil appears with G-dlessness. We are constantly challenged to stay on the side of light, on the side of good, on the side of G-d - that way, we are actually active participants in the process of creation...


For more, see "HaSatan Judaism", Google search term.