Largen's approach to systematic theology is, on the one hand, very straightforward. Her book is "an attempt to do systematic theology in a new way, by considering interreligious engagement as part of the foundation of Christian theology, rather than as a decoration" (1).
Systematic theology in the Christian context has almost always been founded on preceding doctrinal work in Christian theology. Resources for developing theological constructs were and still are typically drawn internally from within the Christian conversation. Although Christianity has always also been at least to some degree involved in inter religious dialogue, typically a work of systematic theology would therefore work out all the doctrinal commitments in advance, and only then ask, "Okay, now that we know who God is in our systematic theology, how can we compare this to how Muslims think about God?"
Largen takes a different approach. Interreligious dialogue is foundational. And it bears fruit in at least three ways.
First, she believes such an approach is "for the sake of the neighbor." In this sense, it is a faithful Christian approach to developing theology. It exhibits love of neighbor.
Second, since God's self-revelation is universal, Christians can and must learn from how God reveals Godself in and through other religious traditions.
Third, Christian faith is both challenged and stretched but also deepened and strengthened by interfaith constructive theological engagement.
The first four chapters of the book engage four major world religions: Hinduism, Judaism, Buddhism, and Islam. They serve as helpful introductions to these faith traditions for Christians, especially seminary students or those preparing for careers in public ministry.
The second half of the book explores three main loci in Christian theology through comparative theology. These include God, humanity, and creation. This portion of the book is influenced by Francis Clooney's seminal Comparative Theology: Deep Learning Across Religious Borders
Largen is intentional about not drawing new conclusions from the comparative theology she is engaging, but instead offers the comparisons as a space to open up new connections for readers.
This is a spectacular book. I plan to read it a second time and even more closely, because I believe it is a premier example of what emerging Lutheran theology looks like in interfaith perspective.