There is support for this from the Word in the preceding parts of this book. It will be said elsewhere that otherwise we could not have been saved.
There are many passages in the Word that show that he took on a human nature, places where it says that he came forth from God, came down from heaven, and was sent into the world. See the following, for example:
I came forth from the Father and have come into the world. (John 16:28)
I proceeded forth and came from God. I have not come of myself; he sent me. (John 8:42)
The Father loves you because you have believed that I came forth from God. (John 16:27)
No one has ascended to heaven except the one who came down from heaven. (John 3:13)
The bread of God is the one who comes down from heaven and gives life to the world. (John 6:33, 35, 41, 50, 51)
The one who comes down from above is above all. The one who comes down from heaven is above all. (John 3:31)
I know the Father because I am from him and he sent me. (John 7:29)
You may see in Section 20 above that being sent into the world by the Father means taking on a human nature.
from The Lord, Section 31
Section 20: Published 3/12 2018