Well, this is where we begin this discussion, I think. Regarding the Trinity, there are many verses which describe and explain the Trinity, God the Father, God the Son and God the Holy Spirit.
Not so for "free will." I find it interesting no one can come up with a verse that supports men's vaunted "free will." Indeed, Paul tells us just the opposite...
"For it is God which worketh in you both to will and to do of his good pleasure." -- Philippians 2:13
Clearly the Scriptures speak of choosing and willing, both for divine and human agency. There are countless references. The question will be, is the addition of the adjective "free" unscriptural? To answer that we would have to understand what is meant by "free."