So what does it mean to be made in the image of God? Well there are several things that it doesn't mean. We aren't ethereal. We aren't a Trinity of persons. We aren't omniscient, omnipotent, omnibenevolent, omnitemporal, and any other omni for that matter. Indeed, there are a lot of ways in which we actually look nothing like God. So how can it be said that we are made in God's image?
Going to Context
Well, if we are going to look at this question biblically, we need to remember the 3 Cs of hermeneutics: context, context, and context. So let's look at the context:
Then God said, "Let us make man in our image, after our likeness. And let them have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth and over every creeping thing that creeps on the earth." So God created man in his own image, in the image of God he created him; male and female he created them. And God blessed them. And God said to them, "Be fruitful and multiply and fill the earth and subdue it and have dominion over the fish of the sea and over the birds of the heavens and over every living thing that moves on the earth." And God said, "Behold, I have given you every plant yielding seed that is on the face of all the earth, and every tree with seed in its fruit. You shall have them for food. And to every beast of the earth and to every bird of the heavens and to everything that creeps on the earth, everything that has the breath of life, I have given every green plant for food." And it was so. -Genesis 1:26-30It is interesting to note that it doesn't go on to describe any divine attributes. However, what it does do is connect the notion of humanity's creation to humanity's authority over the rest of creation. Indeed, I would argue that this is what the concept of being in the image of God means: we have authority over creation.
Authority vs. Sovereignty
"Hold up! How can we have authority over creation, while God is still sovereign?"
To put it simply, having authority is not the same thing as being in charge. When I was a kid, my sister Calin and I had authority over our younger siblings (Calin exercised that authority to a greater extent than I did, but I digress). However, none of us ever confused Calin and me with Mom and Dad. We all knew who really was in charge.
Indeed, it is this kind of fundamental confusion that has lead me to never take Calvinist claims of having "a more sovereign God" seriously. Being more despotic, doesn't make someone more sovereign. It usually just makes them more of a jerk.
In the case of humans and God, the relationship between the two is essentially that of delegation. God delegates a certain amount of authority over to humanity for us to rule over creation. However, what authority we have is only based on our submission to the source of that authority: the Divine King.
The Race of Representatives
Understanding that our authority comes from God's sovereignty, as opposed to being... well, opposed to it, becomes easier when we understand our authority in terms of imago dei. The Hebrew word for 'image' is 'tselem', which is often used to refer to idols.
Now, I am not saying that humans are idols of God, or anything like that. It is very clear in Scripture that we are not to worship each other, but it is important to understand how the word connects to idol worship.In idol worship, one doesn't believe that the idol is truly their god. Instead they believe that the represents their god, or stands in for their god so that they can interact with him/her in a more tangible way. Thus we can consider 'tselem' to mean representation, or representative.
A story from I Samuel works to illustrate this. In this story, the Philistines have captured the Ark of the Covenant, and God has sent plagues of tumors and mice to punish them. Then, in chapter 6, they inquire of their priests what they should do. The answer is to make images (or tselemim) of the mice and the tumors out of gold as an appeasement to God. Note how the images here are not things to be worshiped, but things to represent the tumors and the mice.
Likewise, we can consider ourselves, as human beings, to be things which represent God in creation. We are His delegates, His representatives, and the only power we have is by representing God Himself. Our power is not of our own, but it is an extension of His.
Going to the Story
Now the Bible tells a story. Theologically, we call this the metanarrative, or the overarching story from which our theology is based. When we imagine the image of God in this manner, we find that it influences the way in which we view God's interaction with humanity through history.
At first God sets up humanity to be His representatives among creation. However, humanity rebels and becomes separate from God, deterring humanity's ability to accurately represent Him.
So God sets up for Himself a particular people within humanity to represent Him among humanity. He chooses a single man by the name of Abraham, and sets apart his descendants as the Chosen People, or the Elect. They come to be known as the Israelites. However, at Mount Sinai the Israelites reject God out of fear, and wish to remain separate from Him.
So God sets up for Himself a particular tribe within Israel to represent Him among the Elect. This is the tribe of Levi, and they become the priests of Israel. Indeed, a priest is best understood as someone who represents God to the people, and represents the people to God. If you remember, it was God's original intention for Israel to be a nation of priests (Exodus 19:6). However, because the Israelites rejected this, only the Levites are priests.
Even so, God still continues to show His desire to rule people through a divine representative by establishing the High Priest, to represent Him to the Levites. Therefore, within the OT, you have:
High Priest
/ \
Levites
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Israel
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Humanity
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Creation
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Levites
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Israel
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Humanity
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Creation
Now let's think of the New Testament. In the New Testament, we, the gentiles, are grafted into the vine of Israel, and thus become God's elect as well. However, because of the priesthood of all believers, we manifest God's original design for Israel to be a priesthood to all nations. Thus the Levites and Israel collapse together in the NT picture as the Church. However, we are not grafted in by our own power, but by the power of Christ's sacrifice and resurrection, as the Resurrected One becomes our High Priest. Therefore, in the NT we have:
Christ
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Church
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Humanity
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Creation
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Church
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Humanity
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Creation
Therefore we see that this is how God chooses to rule over His creation. He does not do so through meticulous predestination of all things, though He could. Instead, He chooses to act through people, and He appoints people and peoples for the purpose of representing Him and acting for Him. This is how God manifests His sovereignty.
What Does That Mean for Us?
A few different things. First of all, it means that we are responsible for what we do. We are responsible to God, not just because we are His creatures, but because we have the unique make-up to act on God's behalf. Therefore in everything we do, we represent God as we do it, whether that be consciously or unconsciously. Our sins are not simply bad things that we do, but they are things that besmear God's image, for we are God's image.
Second of all, we have a responsibility. We are supposed to represent God. As humans, we are to represent God in creation and take care of it and nurture it. Do we behave like crazy environmentalists? No. But we treat creation with respect, do what we can to bring out its beauty, but also organize it, and incorporate our own structures within it as any gardener would.
As Christians, we also represent God to other humans. As such, we need to represent Him in both justice and mercy. We don't back down from what God says is true and just, but we behave in a way that demonstrates God's love and affection for humanity. We are delegates of a benevolent king, and we should be benevolent as well. But we are still representing the king, not just some guy with really good ideas.
Third, we need to see that humans are holy: even bad ones and even unborn ones. The way we treat other humans cannot simply be based out of convenience or judgement. People deserve our respect, not because they have earned it, but because they represent God Himself. I would say, biblically speaking, that it is never good to kill a human being (though it is sometimes necessary). Killing other humans soils our hands. Even David, though he fought in God's wars, was too unclean to build God's temple.
Essentially it means that we need to treat humans with respect, not because they deserve it (because we don't), but because they represent God, and God deserves it.