I am the LORD, and there is no other, besides me there is no God; I equip you, though you do not know me (Isaiah 45:5)
“Besides me there is no God”. In a world which is skeptical about absolute truth, here is one absolute which we cannot avoid. We may not be aware of the existence of God, or reject his existence outright, but neither of these things affect the fact that he does exist. A goldfish could carry out a full survey of his bowl, and even peer out through the glass, before concluding that all that exists is contained in his watery domain. It would not mean that the one who pinches in the fish food each day ceases to be. In the end we need to accept that our human knowledge runs out, and that there are things which will remain beyond our understanding.
The absolute truth of the existence of God brings with it other absolutes too. God is good, and so all other goods should be measured against his standard. God is love, and if we want to know what love should look like, we look to him. In other words, God calibrates all the things we might call virtue. They only have some sort of meaning with reference to God.
This is why the Christian can confidently judge whether something is good or bad, there is an absolute standard which we can use. If you reject the existence of God, you have to question if there can be a morality at all. Who gets to decide? Who calibrates what is good, and what is bad. Surely all that is left is just personal taste.
No, to have an absolute God is to us a firm foundation for life and for society. Absolute truths might be rejected, but that doesn’t mean they don’t exist. It just means you don’t like them.