God as a "Jealous" God
There are many places in Scripture where God is described in terms that we use to describe people. This presents few problems when we read about God being compassionate or loving. It presents more difficulty when we read what we would consider to be negative emotions attributed to God. This raises questions for some people. For example, how can anyone justify God as perfect when the Old Testament seems to describe him with traits that we as human beings should not have, such as jealous or envious?
One problem that gets in the way of dealing with this question is the assumption made by many Christians that the Bible is absolutely literal in everything it says and presents nothing but propositional truths without any use of symbolism, metaphor, or any literary features that are part of human language. This view assumes that the Bible just tells us what to believe about everything, totally disconnected from any human culture or means of expression. So, if the Bible says something, it "means what it says" on a very literal level. If God is said to be "jealous," then he is really "jealous," and we should not question why he is or if he should be. It's just how he is.
This propositional view of Scripture leaves us with a Bible that is nothing more than a collection of facts about everything we might want to know given directly by God in the form in which we have it in the Bible. This allows for little human input into Scripture (which arises from assumptions about the total and unredeemable corruption of humanity) and leads to a superficial literalism when we read Scripture. That is, this leads to the view that the Bible should only be taken at face value, and we should hear what it says as a direct description from God about "how things really are." While I would want to affirm that on one level there is a simplicity to the message in Scripture, there is also more to it than meets the eye, and it sometimes takes some effort to understand.
So the real issue, then, comes down to how we understand Scripture and the nature of the Bible as it uses such terms to talk about God, rather than simply assuming that God is the same thing as our human descriptions of him. In other words, we have to ask what this human metaphor intends to say about God from the perspective of the culture and literary context in which it was used. So, a better way to formulate the question is: what does the biblical testimony intend to communicate when it describes God as "jealous" or "envious" beyond actually attributing to God those negative human emotions as part of his character?
Many Christians affirm, and especially from the Wesleyan theological perspective, that the Bible is both a human book and a divine book, God’s word in human words. That means that the message of the Bible is revealed/inspired by God, but that human writers also wrote from the perspective of their own time, knowledge about the world, culture, world view, and language, as well as the particular needs of the community they were addressing. God’s message was communicated by people, under the leadership of God, but in their own unique way (see Revelation and Inspiration of Scripture).
As a result, the message of the Bible is "incarnated" truth, a message (God’s word) contained within the means of communication (human words). As applied to this question, we must realize that God is described in the Old Testament, and in the New Testament as well, in the language of a particular people and culture, expressing magnificent truths about God within the confines of certain means of expression. So when they use the expression, for example, "God brought us out of Egypt with a mighty hand and a strong arm," this does not intend to portray God as a king sized body builder. We should understand this as an anthropomorphism, describing God’s power and majesty in very human metaphors, the only ones we have at our disposal. The message does not have to do with how big God’s arms are, or even whether he has arms, but about God’s power and the Israelites’ experience of that God on the banks of the Sea of Reeds. Attention must be paid to what the author is intending to say by the use of certain expressions, metaphors, and symbols rather than taking the particular words and expressions as truth in themselves.
In particular, the references to God as a jealous God draw upon the human emotion and use it as a metaphor to express something about God. To leave it on the literal level assumes that the human emotion, which is almost always negative, is a description about how God "really is." However, to take this as an anthropomorphic description about God allows it to move beyond the negative human emotion.
The Israelites existed in a world and among people who believed in the worship of many gods. Their greatest religious threat came from Canaanite fertility religions that personified the forces of nature into deities (see Ba'al Worship in the Old Testament). The Canaanites could add Yahweh, the warrior God of the Israelites, to their worship as another of the nature Gods. This polytheistic world view was not threatened by another god. However, to the Israelites, the God of Abraham, Isaac, and Jacob, the God of the Exodus and the covenant, was not just another god, He was THE God. The Israelites recognized Him as the only Sovereign Creator God. The metaphor often used to make this claim was the metaphor of God as a jealous God. He would not simply be added to the other nature deities, because he had created the aspects of nature that the Canaanites worshipped. It is not that this describes some metaphysical attribute of God, only that it was Israel's way of expression their conviction that God was the only God that mattered, that there could only be ONE God (cf. Deut. 6:4).
Hosea takes this metaphor and makes it positive, as he compares God’s relationship with Israel in the imagery of a marriage. The basis of that relationship is love, and "jealously" is a way to describe the love that a husband has for a wife who is unfaithful and works as a prostitute. This "jealousy" is a way to describe the hurt and deeply felt pain of betrayal and loss because of the unfaithfulness of the wife (Israel) in a relationship in which she had pledged herself to her husband who had loved and cared for her (God).
So when biblical writers apply this term to God, they are affirming that He, as Creator and Deliverer, is the only God worthy of our worship. To describe God as "jealous" was Israel's way of countering the polytheism of the surrounding peoples, and of proclaiming God as the only God deserving the love and allegiance of humanity.