From Raymond Brown, The Gospel According to John, vol. 29, 1966, pp 523-24.
The Memra of the Lord in the Targums is not simply a translation of what we have spoken of as “the word of the Lord”; rather it is a surrogate for God Himself.
If in Exod 3:12 God says, “I will be with you,” in the Targum Onkelos God says, “My Memra will be your support.”
If in Exod 19.17 we are told that Moses brought the people out of the camp to meet God, in Targum Onkelos we are told that they were brought to the Memra of God.
If Gen 28.21 says, “Yahweh shall be my God,” Targum Onkelos speaks of the Memra of Yahweh.
In sum, it seems that the Prologue’s description of the Word is far closer to biblical and Jewish strains of thought than it is to anything purely Hellenistic [Greek].
In the mind of the theologian of the Prologue the creative word of God, the word of the Lord that came to the prophets, has become personal in Jesus who is the embodiment of divine revelation.