It is permissible to perform an act that is permitted on the Sabbath, despite the fact that it is possible - but it is not an absolute certainty - that, [as a result of one's actions], a forbidden labor will be performed, provided one does not have the intent to perform that labor.
What is implied? A person may drag a bed, a chair, a bench and the like [on the ground] on the Sabbath, provided he does not intend to gouge out a groove in the earth while dragging them. Therefore, even if he did gouge out [a groove] in the ground [while dragging them], it is of no consequence, for he did not have this intent in mind.
Similarly, a person may tread on grass on the Sabbath, as long as his intent is not to uproot it. Thus, should it be uprooted, that is of no consequence. Also, a person may rub powdered herbs and the like over his hands, provided he does not intend to remove his hair. Therefore, if the hair is removed, it is of no consequence. Based on the same rationale, one may enter a narrow opening on the Sabbath even though, [while doing so,] one causes pieces of the wall to fall. Similarly, it is permissible to perform any act with similar repercussions, provided that one does not have the intent of doing so.