This is to say that there are themes in the writings of John Calvin, a French Reformation leader, that I take as my own while leaving other parts behind. I thought I'd highlight what some of the themes I've taken.
1. The natural world tells us all of God that we are in a position to know. That's a robust natural theology! Special revelation is not new information beyond our world. It illuminates something already at play in our world.
2. Theology starts with anthropology. To know something of God is to know something about ourselves and our relationships to each other and our wider world.
3. Sin, pride, impiety is an over (or under) estimation of ourselves in relation to one other and our world. Any number of cruelties (to use Niebuhr for a moment) against each other and nature occur when we ignore those relations.
4. Sin and grace are bigger than individuals. They both indicate significant features of a world that draw us either to inordinate self regard or other regard. The ambiguity is living in a fallen world that yet gives signs of God's redemptive purposes.
4. Calvin was just as able to draw from Seneca as Scripture. As a French Humanist he saw the Christian tradition as a wisdom tradition, a philosophy almost that could draw from the best, including non Christian resources.
5. Like Augustine, Calvin also believed that all knowledge was from God. Science, literature, philosophy, any field and discipline was a gift not something to be wary of or at war with. In fact it can set us on a path to discern our proper place in our world and relations.
6. God's redemptive work is for the whole of creation. So there is no way to cut off some part of the world, the secular, or some area of life as not religiously significant.