Puritan Board Doctor
Him, being delivered by the determinate counsel and foreknowledge of God, ye have taken, and by wicked hands have crucified and slain. (Acts 2:23, KJV)
It's only a totally sovereign God that can maintain man's freedom and responsibility, which would otherwise be subject to chance and fate, nature and nurture.
How He does it, is as far as I am aware, a mystery, but if He isn't totally sovereign there is room for impersonal and irrational chance and fate to get a foothold in the door of the Universe and for Man's freedom and responsibility to be crushed under their jackboots.