The translation of the Authorised Version, as it renders the same Hebrew word "Satan" in one place and "adversary" in others, tends to mislead. But the following portions of Psalm cix. will show how the word was employed:—
Verse 6—"Set thou a wicked man over him, and let Satan (an adversary) stand at his right hand." Verse 20—"Let this be the reward of my adversaries (my Satans)." Verse 29—"Let mine adversaries (my Satans) be clothed with shame."
The Old Testament Satan, therefore, is not a particular person at all, but a character which would apply to any one acting in opposition to another. Let this view be tested by the following instances:—
Numbers xxii. 22—"And God's anger was kindled because he (Balaam) went, and the angel of the Lord stood in the way for an adversary (a Satan) against him." Here the Satan is the angel of the Lord. 2 Sam. xxiv. 1—"And again the anger of the Lord was kindled against Israel, and he provoked David to number Israel." 1 Chron. xxi. 1—"And Satan (an adversary) stood up against Israel, and provoked David to number Israel."
These two passages, on comparison, show that Jehovah himself was the Satan of David in this instance.
Job i. 6-12; ii. 1-8.—On the day when the sons of God came to present themselves before the Lord, Satan (the adversary) came also among them. The Lord asked whence he came. Satan (the adversary) replied, "From going to and fro on the earth." Then followed a discussion with reference to Job's piety. Satan (the adversary) suggested that Job's service of God was not for nought; that if the Lord took away his wealth he would curse. The Lord replied, "Behold, all that he hath is in thy power; only on himself put not forth thine hand." Soon Job lost his cattle, his servants, his children. He resignedly said, "The Lord gave and the Lord taketh away, blessed be the name of the Lord." On a second similar occasion Satan (the adversary) suggested that if Job's person were touched he would "curse thee (the Lord) to thy face." The Lord said, "Behold, he is in thy hand, but spare his life." Satan (the adversary) smote Job with sore boils from head to foot. But he said, "Shall we receive good at the hand of God, and shall we not receive evil?"
Here Job's adversary came into the presence of the Lord, among the sons of God, and discussed Job's case with Jehovah himself. Is the conception, then, that he was a messenger of the Lord, walking up and down through the earth, contemplating its inhabitants; that his observation had shown him—if men then were like what they are now—that calamities were not borne with patience, that penury and complaints, losses and curses, went together; so that, when asked his opinion about the well-to-do Job, he would not give him credit for being different to his fellows? In this way he became his Satan or adversary. This appears to be what the writer would convey. But how unlike the "roaring lion" of the New Testament.
It will be noticed how strictly the power of Job's adversary is limited to what Jehovah specifically permitted. So much so, that when the calamities actually fell on Job he described them as from the Lord. In no way whatever does the Satan here mentioned act in opposition to Jehovah.
Zech. iii. 1, 2—"And he showed me Joshua the high priest standing before the angel of the Lord, and Satan (the adversary) standing at his right hand to resist him. And the Lord said unto Satan (the adversary), The Lord rebuke thee, O Satan, even the Lord that hath chosen Jerusalem, rebuke thee: is not this a brand plucked out of the fire? Now Joshua was clothed with filthy garments, and stood before the angel."
The conception here may be this: Joshua, with the filthy garments (figurative of the sins of Judah borne by the high priest, their representative), standing before the angel of the Lord, was resisted by "the adversary," or angel of divine justice. But the latter had to give way before the restoration of the divine favour. Or, more probably, "the adversary" may have been one of those who opposed the work of rebuilding Jerusalem, as mentioned in the Book of Ezra.