If we don’t understand this doctrine or how we got it, we’re left with flimsy answers to important questions–questions which become barriers to faith for some people. We may find ourselves having to shrug at crucial Christian beliefs, or worse, provide answers that drive people further away from Christ.
Hypostatic union is how Christians explain the relationship between Jesus’ divine nature, his human nature, and his being. It means that Jesus is both fully God and fully man. Jesus has all of the characteristics that are true of a person, and all of the characteristics that are true of a divine being. Both natures fully exist in one person.
For centuries, the church struggled to define the relationship between Jesus’ divine nature and his human nature, and numerous heretical ideas emerged to try and explain it that either compromised Jesus divine nature or reduced the significance of his humanity. Hypostatic union helped the church rule out these incorrect explanations.
If you put an apple and an orange into a blender and mix them together, you can’t say that the end result is still “fully apple” and “fully orange.” It’s a new substance—a combination of the two. Jesus’ divine and human natures exist together in such a way that they are united in one person, but “unblended.” They each retain all of their qualities without interfering with the other.