Much like the Greek goddess of Wisdom, Sophia, Second-Temple Jews believed in a female hypostasis who existed with God before the world began. According to the Hebrew Bible and the New Testament, this quasi-goddess was the means by which Yahweh created the world (Prov. 8; John 1:3), effectively replacing Asherah worship while also assimilating the Greek god Hermes in the process.
First, what is a "hypostasis" (Greek: ὑπόστασις)? Well, it's a little hard to explain since it's one of those technical philosophical terms that does not have a very good equivalent in English. But a "hypostasis" is basically the personification and deification of a divine attribute. The line of reasoning for the ancient Hellenistic world went something like this:
God is wise; therefore, God possesses wisdom.
If God possesses wisdom, then Wisdom (capital 'W') must be an entity that is separable from God himself.
But since God is eternally wise, then that separable Wisdom-being must likewise be eternally existent.
Therefore, Wisdom must be a type of deity who has eternally existed alongside God.
For Second-Temple Jews who had assimilated much of Hellenistic beliefs into their own religious worldview, they believed Lady Wisdom once tried to dwell with humanity on earth before being driven away by human sin (Sirach 24; 1 Enoch 42). The story parallels the goddess Justice in Greek mythology and was adopted by Christians who said Christ (the divine Logos) dwelt among his people, although humanity rejected him (John 1:11).
When actual goddess worship was banned immediately after the Babylonian Exile (during the reforms of Nehemiah and Ezra), post-exilic priests and scribes transformed Yahweh's consort, Asherah, into the figure of Lady Wisdom located throughout the book of Proverbs. Though originally an actual deity, Jewish elites gradually interpreted Lady Wisdom as a metaphor or figure of speech in order to maintain a sense of monotheism.
This made sense for post-exilic Jews to replace Asherah with Lady Wisdom since Canaanite literature portrayed Asherah as a cunning female who regularly influenced the high gods, El and Ba'al. Indeed, Asherah was co-creator of the cosmos with El.
When the author of the Gospel of John changed Lady Wisdom into the Logos, the evangelist may have been translating Jewish mythology into Greek terms while also incorporating concepts about the Greek god, Hermes (since Jesus was a man). He was basically the male counterpart to Sophia. For example, Hermes was often called Logos in Greek literature because he expressed the reasoning of his father, Zeus, and interpreted his father's wisdom for humans to understand. Moreover, the subordinate god Mercury (Roman Hermes) was incarnated in human flesh during a time of crisis and became a king, leading his people to peace before ascending back up to heaven.
Believing Jesus to be the incarnation of the divine Logos, certain high Christologies in the Christian church appear to have combined Lady Wisdom and Hermes into the single figure of Christ where his goal was to express and interpret the will of his father deity.