My transgression is sealed up in a bag, and thou sewest up mine iniquity.
It was customary with the ancients to use a seal oftentimes where we use a lock.
Money was counted and put into a bag, then a seal put on it. Thus a seal might be put to a bag as evidence that its contents need not be counted again.
The idea here is that Job’s sins were all numbered, put into a bag, and carefully stored away for future reference; God watched over them as one watches over a treasure.
– Dake A.R. Bible: page 425