Barth says that the story of Job is all about (surprise) freedom.
“Freedom is not caprice. The relationship [between Yahweh and Job] could not be other than it is. The intercourse could not take a different course. yet there can be no question of any necessity of the relationship or ineluctability of the intercourse. For it is all grounded in and fashioned by free electing and disposing on the part of God and equally free obedience on that of Job.”
Barth asks, “How does Yahweh come to be the Partner of the man of Uz in the drama of this history? He obviously is this with great seriousness and intensity. He manifestly could not be otherwise. By why is He? … [the story] is one long demonstration of the boundless confidence which He has set in him and the fidelity which he has plainly sworn to him. But it is not, as the false and lying theology of the three friends presupposes and maintains, a moral or juridical law which is secretly above Him. Along the lines of His unchangeable fidelity, it is His self-determined and to that extent free and royal conduct.” (CD IV.3.1, 386-387)
Barth says that Job (with qualifications) is a prefigure of Jesus, particularly in the sort of relationship that he has with Yahweh. Satan asks if Job fears God “for nothing,” that is, isn’t God’s blessings on Job what actually secure their friendship?
Certainly part of the answer of the author is, ‘no.’ Their relationship is based on freedom, a freedom which is ultimately grounded in the sovereign love of God.
At the same time, Barth is characteristically opaque in drawing this out: he asks, “And how does Job come to be the servant of God? The answer is that he simply is.” He of course grounds this “being” in the idea of freedom “to be.” He says, “Job would not be Job if he were not free to receive both evil and good from God. This implies that he fears and loves the free God as such…” That is, his loyalty and allegiance to God is not based on a particular program or contract. It is rather genuine and free love and loyalty between persons.