To some degree, the incarnation of Christ will always remain mysterious to us: how can God become man and yet remain God? There is mystery here, I say, and the volumes that theologians have written on this topic can hardly be condensed to a short paper column. So I will offer a simple devotion for this Christmastime.

The author of Hebrews highlights for us some astonishing truths that are possible only because Jesus Christ was fully human: “In the days of his flesh, Jesus offered up prayers and supplications, with loud cries and tears, to him who was able to save him from death, and he was heard because of his reverence. Although he was a son, he learned obedience through what he suffered. And being made perfect, he became the source of eternal salvation to all who obey him” (Hebrews 5:7–9).

These are truly statements that, if we didn’t find them in the Bible, we might hesitate to think them (much less say them out loud), lest we be considered irreverent. Jesus prays with tears? Jesus learned obedience?! How does the perfect Son of God learn obedience? Wasn’t Jesus always obedient? By turning our heads this direction, the author of Hebrews forces us to look squarely at the humanity of Christ, the humanity that is his because of his incarnation.

These are not just abstract theological questions; for believers, these verses are foundational to the mercy we find in Christ. The verses that immediately precede this passage tell us that the full humanity of Christ is the basis upon which he can be a merciful priest for us (Hebrews 4:15). He knows, in a fully experiential way, what it is to come to the Father in prayer as a reverent son (even though he is also the Son). He knows what is to pray with loud cries and tears. We must think here, quite obviously, of the Garden prayer, in which Christ, agonizing in prayer, submits himself to his Father’s will. Do we not find encouragement here, that we share these struggles with Jesus himself?

Further, Jesus knows what it is to learn obedience. The Gospels tell us that the young Christ grew in wisdom, stature, and favor with God and man (Luke 2:52). These verses most clearly show us the fullness of the humanity of Jesus; his growing in favor with God and man and his learning obedience show that his perfect humanity was no sham, no mere show. While the Bible teaches that Jesus is the sinless man, it also here tells us that his experiences, and particularly his sufferings, were how he grasped the full human concept of obedience. And we share this with the Son of God as well. Who among us has not grown to know obedience to the Father more clearly through our suffering?

And so, as we celebrate the Christmas season, the rejoice in the full humanity of our Savior, who has mercy on us because he shares our flesh.