The Greek word λόγος is a prevalent concept in the first century Greco-Roman world. It has many meanings like divine principle, reason, word and revelation. All of these views regards the λόγος as impersonal but Christians went beyond this age-old tradition and reinterpret the λόγος from personification to a real person subsisting.
John the Apostle wrote that the λόγος is God by nature and hence, teaching us that the λόγος is a person because God's nature includes personality.
John 1:1 is clear that the λόγος is with God and is also God.The immediate context reveals how is the λόγος God by nature and this is by being the μονογενὴς of the Father (John 1:14,18).
God = Person ( the Father- John 1:14)
λόγος =Person because God by nature ( the μονογενὴς in the Father's bosom - John 1:18)
But in the second century, the Logos Theology of the Greek and Latin Apologists began teaching that the λόγος is not an eternal person like what was taught in John 1:1 but rather, they adopted the Stoic terms of "logos endiathetos" ( Reason within) and "logos prophorikos" ( Reason expressed from the inside out) in order to teach that God is not an eternal Father and that the λόγος is not an eternal Son although they still teach that the Son is God and is of same nature with the Father.
Against Praxeas Chapter 7
Dialogue with Trypho Chapter 61
Now this is my question:
Why did the second century Apologists adopt the Stoic distinction of the "logos endiathetos" and the "logos prophorikos" to teach Christ's deity?