Let us first state what the orthodox Christian teaching on the person of Jesus Christ asserts. When it comes to the doctrine of the person of Christ (what theologians call Christology), there are four cardinal truths that need to be believed:

1. Jesus Christ is fully divine
2. Jesus Christ is fully human
3. Jesus Christ has two distinct natures
4. Jesus Christ has these two natures united in one person

Now the orthodox teaching on the person of Jesus Christ was the subject of much early church disputes. In fact, the first four ecumenical councils of the early church dealt with each of those four statements above, affirming their truth while denying the heresies that sought to distort these teachings. The final, orthodox statement on the doctrine of the person of Jesus Christ was put forth in The Chalcedonian Creed of 451 AD. That creed says, in part:

We, then, following the holy fathers, all with one consent, teach men to confess...one and the same Christ, Son, Lord, Only-begotten, to be acknowledged in two natures, inconfusedly, unchangeably, indivisibly, inseparably; the distinction of natures being by no means taken away by the union, but rather the property of each nature being preserved, and concurring in one Person and one Subsistence...

Now that’s a mouthful, but the portion in bold is important. The human and divine natures exist in the one Person, Jesus of Nazareth such that there is no confusion between the two, no change between the two, no division between the two, and no separation between the two.

In our own confessional standards, Belgic Confession article 19 states in part:

We believe that by this conception the person of the Son is inseparably united and connected with the human nature, so that there are not two Sons of God, nor two persons, but two natures united in one single person; yet that each nature retains its own distinct properties.

That last statement quoted from the Belgic Confession is very important. It means that the divine nature loses none of the properties of divinity, nor does the human nature lose any of the properties of humanity by virtue of the union of the two natures in the one person of Christ.

We see this Biblically when we learn that Jesus “kept increasing in wisdom and stature, and in favor with God and men” (Luke 2:52). Jesus grew in wisdom and knowledge. The human nature wasn’t born knowing all things. Jesus had to be taught just like every other human child. Jesus got hungry, became tired, experienced the full range of human emotions including deep sorrow and anger. He was even subject to death. Similarly, the divine nature never ceased being infinite, eternal, and unchangeable. In the very first verse of John’s Gospel, we read the famous words, “In the beginning was the Word, and the Word was with God, and the Word was God...And the Word became flesh, and dwelt among us” (John 1:1, 14).

But what about the relationship between the two natures? How does that work? Well, it shouldn’t surprise us to learn that theologians have come up with a fancy Latin phrase to label this called the communicatio idiomatum, or the “communication of properties.” Joel Beeke, in Reformed Systematic Theology, Volume 2, states, “The communication of properties is personal — that is, the divine nature with all its properties is united as one person with the human nature with all its properties. Hence, the one Christ Jesus displays divine attributes and performs divine acts, and likewise displays human attributes and performed human acts” (p. 848).

In other words, we should not be surprised when Jesus Christ, the person, does things that could, at one time, be attributed to His divine nature, and at the other time, attributed to His human nature. We should never get in the habit of saying, “well the divine nature did that,” because the two natures are forever and inseparably linked together in the one Person. So we can say “the Son of God died,” because the Son of God took on a human nature in the person of Jesus Christ, and Jesus died. We can also say “the Son of Man gives life” because Jesus, who is both human and divine, gives life. We can’t say “the divine nature died” or “the human nature is eternal” because that would be to separate the two natures from the one Person of Jesus Christ.

So as it pertains to Jesus’ knowledge of the specifics of His return, the best way to answer this question is to say that this particular knowledge wasn’t imparted to the human nature. Another thing we need to understand is that the Son of God, the Second Person of the Trinity, as Paul says, “emptied Himself, taking the form of a bond-servant, and being made in the likeness of men” (Philippians 2:7). In other words, the Son of God relinquished the prerogatives of deity during the incarnation, and that could include certain aspects such as knowledge of His own return in glory.

One final thing in closing. This is all a glorious mystery. We can only say with confidence what the Biblical record states definitively. If we attempt to explain too much or go too far, we run the risk of falling into heresy. As long as we stick within the boundary of those four statements at the beginning, we should be okay!