Essentially what they're saying is that life's messy and complex and there are no answers, you just have to 'accept the mystery' and deal with it.
It's there in the epigraph ("Receive with simplicity all the things that happen to you"), Larry's discussion of Heisenberg's uncertainty principle, Clive and his father's attempts at bribery ("Please, accept the mystery"), the references to the Book of Job and various other things.
Here's part of the story of Job - https://en.wikipedia.org/wiki/Job_(biblical_figure)
It begins with an introduction to Job's character—he is described as a blessed man who lives righteously in the Land of Uz. The Lord's praise of Job prompts an angel with the title of 'satan' ("accuser") to suggest that Job served God simply because God protected him. God removes Job's protection, and gives permission to the angel to take his wealth, his children, and his physical health (but not his life). Despite his difficult circumstances, he does not curse God, but rather curses the day of his birth. And although he anguishes over his plight, he stops short of accusing God of injustice. Job's miserable earthly condition is simply God's will.
In the following, Job debates three friends concerning Job's condition. They argue whether it was justified, and they debate solutions to his problems. Job ultimately condemns all their counsel, beliefs, and critiques of him as false. God then appears to Job and his friends out of a whirlwind, not answering Job's central questions. Job, by staying silent before God, stresses the point that he understands that his affliction is God's will even though he despairs at not knowing why. Job appears faithful without direct knowledge of God and without demands for special attention from God, even for a cause that all others would declare to be just. And the text gives an allusion to Job 28:28 "And unto man he said, Behold, the fear of the Lord, that is wisdom; and to depart from evil is understanding"
The parallels are pretty clear from the off, you've got Larry, a man whose life quickly falls apart, Sy, the outside party who takes everything from him, the various rabbis and friends whom Larry discusses his situation with and the tornado/whirlwind which appears at the end. It doesn't follow the story of exactly, but the it's essentially the same story with a few Coen-esque tweaks.