Nahum 1:2 reads God is jealous, and the Lord revengeth; the Lord revengeth, and is furious; the Lord will take vengeance on his adversaries, and he reserveth wrath for his enemies.”

Here prophet Nahum describes God as a jealous God and as one who takes revenge on his adversaries/enemies.

One one hand, jealousy is a vice when it is driven by covetousness and lust, while on the other, it is a virtue when it is driven by compassion and love. God’s jealousy is a godly (virtuous) jealousy (2 Corinthians 11:2), driven by compassion and love.

The two main contexts in the scripture, in which God is described as a jealous God are:
first, in the exclusivity of worship, and
second, in the defense of his people.

First and foremost, God commanded that we must not bow down to, nor serve any idols (Exodus 20:5), for he is a jealous God. We must not worship any other gods, for God is jealous (Exodus 34:14), and his name is Jealous (Exodus 34:14). He is a consuming fire (Deuteronomy 4:24) and his jealousy burns as fire (Psalm 79:5) consuming idolators and adulterers who go after things which are not God (be it our family, finance (work) or fun (pleasures)) (Deuteronomy 32:21) .

In the book of Nahum, the context of God’s jealousy stems from his compassion for his people (Joel 2:18), because the Assyrians had continually afflicted Judah, his people. As a jealous God, God is zealous to defend the people he loves against those who threaten and oppress them.

While God reserves his love for his people and friends, he reserves his wrath for their enemies, who are in turn God’s enemies. We know this because when Saul encountered Jesus on the road to Damascus, Jesus did not ask him “Saul, Saul, why are you persecuting the Christians?” but instead asked “Saul, Saul, why are you persecuting me?” (Acts 9:4)

Points to ponder:
While god reserves his wrath for his enemies, he reserves his love for his friends, and Jesus called his disciples, not servants, but friends (John 15:15). Jesus said, greater love has no man than this, that he lays down his life for his friends and Jesus demonstrated such love that while we were still sinners (and enemies of God, deserving his wrath), he died for us.

God wants our exclusive allegiance to him for he commanded that we should worship no other gods for he is a jealous God (Exodus 34:14). God does not want us to be belong to someone else. He is jealous, not of you and me, but for you and me. Infact his name is Jealous and he is a jealous God (Exodus 34:14). He loves us and is compassionate toward you and me and will defend us against those who threaten and oppress us. God is jealous for and jealous over you and me.

Nahum 1:2 (KJV)
2 God is jealous, and the Lord revengeth; the Lord revengeth, and is furious; the Lord will take vengeance on his adversaries, and he reserveth wrath for his enemies.