Seeking information about what the Bible has to say concerning the subject of "Jealousy" .
Most references to jealousy in the Bible are along the lines of Exodus 34:14-"For thou shalt worship no other god: for the LORD, whose name is Jealous, is a jealous God." They talk about how God wants his people to worship him and him alone. I suspect, though, that you are asking about jealousy between people. So I will get back to the idea of God's jealousy shortly.
The Bible really has only three passages that deal with the jealousy of one person concerning another. Let us look at these first.
One of those, Song of Songs (Song of Solomon) 8:6, says "jealousy is cruel as the grave: the coals thereof are coals of fire, which hath a most vehement flame." It would seem, then, that jealousy can be a dangerous thing. While it may cause harm to the object, it causes more harm to the one who harbors the feeling. You see, uncontrolled jealousy can cause us to destroy our own lives. If we give in to it we follow up with distrust, enmity, even hate. Uncontrolled jealousy is not a sign of love, but of selfishness.
Proverbs 6:32-35 says: "whoso committeth adultery with a woman lacketh understanding: he that doeth it destroyeth his own soul. A wound and dishonour shall he get; and his reproach shall not be wiped away. For jealousy is the rage of a man: therefore he will not spare in the day of vengeance. He will not regard any ransom; neither will he rest content, though thou givest many gifts." As I read this, the wise man is saying to avoid adultery because the wronged husband, in this case, may be rightly jealous and demand more satisfaction than you are willing to give. Perhaps the jealousy goes out of control and will not be satisfied by the offer of payment for the wrong. But in essence it is a righteous jealousy because the wronged husband could expect other men to stay away from his wife.
The third passage is too long to quote here. It is Numbers 5:11-31. This is the law for the Jews concerning a method (possibly miraculous) to determine if a man's jealousy is justified. Essentially it says that if a man suspects that his wife is bearing another man's child he shall take her to the priest. They go through a ceremony that involves her drinking a sort of potion. If the child is someone else's the potion, or just the stress of the ceremony, will cause her to miscarry. However, if the child comes to full term she will be held guiltless; it is his child. Whether this was ever used or not is never indicated in scripture. It may have been enough of an incentive to make a woman admit her adultery just because of the oaths she was required to take. The only thing I think we can take from this passage is that there are times when a man may become jealous and suspicious. He should not let that jealousy fester in him, but may take certain legal action to determine her guilt or innocence. Perhaps the modern equivalent would be a dna test. However, one should be careful not to go to extremes on a whim, lest one drive his wife away.
Those are the passages dealing with a man's jealousy about his wife. But I think we can learn about a man and wife from God's jealousy as well. (I specify a man and wife, because jealousy is only appropriate if one has a reasonable expectation of faithfulness, which expectation can only come through marriage.) God, through several of the prophets (Isaiah, Jeremiah, Hosea, Ezekiel, Zephaniah, and others) expressed that he was a jealous God because his people Israel, his bride, had gone off and committed adultery with other gods, which were no real gods. This jealousy was a righteous jealousy. That is, he had the right to expect faithfulness and had proof of unfaithfulness. That last is important. God didn't give in to idle suspicion, but acted on proof, on the nation of Israel flaunting their adultery in his face. God did not give in to uncontrolled jealousy, but offered the offending wife an opportunity to make amends and become faithful to him again. In his jealousy He did not cut them off altogether. In like manner, man's jealousy should be founded on a reasonable expectation of faithfulness (marriage) and a reasonable suspicion that one has broken that covenant. Mere flirting is not a sufficient cause for jealousy. Man can control that jealousy. We have to make choices, but one of the choices we make should be self-control. And jealousy should not close off all hope of reconciliation. Extreme, uncontrolled jealousy of the selfish variety wants to punish and divorce. God's righteous jealousy wants to bring the adulteress back into the covenant of marriage for keeps.
I hope this clarifies matters and is of help.