In this video, Dr. Joel Kim describes why it is necessary to affirm the deity and humanity of Jesus Christ.
Why is it important for us to affirm the deity, “God-ness” of Jesus and the humanity of Jesus? The church has spoken often of Jesus as truly divine and truly human. Fully divine and fully human. In fact, so many controversies of the past involved this understanding of the two natures of Jesus Christ. We come to recognize, in the early churches, that there are some who tried to understand this but sometimes adopted positions that are erroneous. Sometimes you see that Jesus was adopted into divine-hood. Others would say that He is primarily human. Or others would say that the two natures are separated. There are even others who say that they are actually conjoined in some mixture, in some ways. The church took pains—in fact, multiple confessions, Nicea in 325, Chalcedonian Creed of 451—to remind us that the two natures of Christ should not be confused, changed, divided, or separated.
Now the language is being utilized to provide guardrails for us in understanding the two natures of Jesus. Why would the church spend so much time and energy into defending the two natures, the fully divine and the fully human nature of Jesus? Part of that is because they want to be accurate and true to the Word, and this is how the Bible teaches who Jesus is to remind us. They also recognize that there are significant theological implications that are at play here. To give you one example, something like the atonement. We come to realize that the God-man, coming, living, and dying on our behalf is an important part of our God’s plan of salvation for us. We are too sinful to atone for our sins, to die for our sins. We have not lived a perfect life. None of us has, and so therefore, we cannot die for our sins.
But yet someone must pay for our sins. This is the understanding that we have because the righteousness of God demands it. But even if we were to find a perfect man, that man cannot die for another man’s sin because He can not, beyond Himself, pay for anyone’s sin. So here we’re in a predicament to satisfy God’s righteous demands. Yet at the same time, the sinfulness that all human beings have, and this is where God's solution is the sending of His Son, who as a human being lived a perfectly righteous life. And then this perfectly righteous Son, who knew no sin, then dying on our behalf. And not only is He able to withstand the judgment of God, but the effect of His righteousness and judgment can have implications for all those who are in Christ Jesus. Only a God-man can die for our sins with effectiveness for all. Therefore, the only mediator between God and man, the Scripture reminds us, is Jesus. All that to simply say: if Jesus is not fully divine and fully human, it has implications far beyond just the two natures of Jesus, to go into areas of theology where it disrupts our understanding of what Scripture teaches us about our salvation.