Was the OLD TESTAMENT JEALOUS REVENGEFUL GOD merciful? HOW? Aren't they mutually exclusive?

The "New Testament" God is also Jealous, vengeful and merciful.

God made us.  We know that "part" of our earthly fathers goes into making us (sperm).  We might say that "part" of God went into us when He made us.  NOt sperm or anything like that, but rather His spirit (not the Holy Spirit).  God breathed life into us.  From Him to us. (I'm speaking  oversimplified).  We are "part" of Him and He wants that part back (to live with Him eternally).  So He's jealous when anything tries to come between Him and His children (We're the same with our kids).

God is vengeful, but not spiteful (as we see vengeance).  God is vengeful as in He will administer justice.  He will "even things out" (so to speak).  We want justice too.  That's why we have a court system.  We levy fines, assign jail time, even execute ..  all to deliver justice.  We bribe and lie to try to escape human justice,  However, no one can escape God's justice.   He knows all (intentions, excises). That's why we're to leave vengeance to God.  

God is merciful.  If he weren't, we wouldn't be here.  EVERY person has rebelled against God.  EVERY person has tried to usurp His authority and power.  The penalty for such rebellion is death.  But God in His mercy doesn't simply blot us out.  Instead He went through heaven and hell to make a way for us to be redeemed.   Jesus.  Of course, anyone who doesnt come to Jesus for redemption, will eventually have to face the full wrath of God for their rebellion.

We want to define God in our terms, create Him in our image.   But God is not human.  He is superior to us in every way, shape and form.  He is OUR creator, not we His.  We must see God as He IS not as we want HIm to be.