Luke1:31 And behold, you will conceive in your womb and bear a son, and you shall call His name Jesus. (35) And the angel answered and said to her, The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore also the holy thing which is born will be called the Son of God.
The Lord's two essences were not merely added together; rather, in the conception of the Man-Savior the divine essence and the human essence were mingled. Some who misunderstood this mingling said that it caused a third nature to be produced, something which is neither divine nor human. To say that with respect to the Lord Jesus...is heretical.
However, we wish to make it clear that this is not our understanding of the word "mingle." We agree with the first definition of this word given in Webster's Unabridged Dictionary: mingle--"to combine or join (one thing with another, or two or more things together), especially so that the original elements are distinguishable in the combination." According to this definition, when two or more things are mingled together, their original natures are not lost but remain distinguishable.
We may use tea as an illustration of mingling. When tea is mingled with water to make a beverage, neither the essence of tea nor the essence of water is lost. Instead, both essences remain...they do not produce a third nature, something which is neither tea nor water.
Our Savior was conceived of the divine essence and born of the human essence. Therefore, He is a Person with two essences--the divine and the human--mingled together without a third nature being produced. Although the Lord has two essences, He is still a single complete Person, One who is both God and man.