Luke 14:5
Then he asked them, if one of you has a child or an ox that falls into a well on the Sabbath day, will you not immediately pull it out? — the child-or-ox-in-a-well argument is the Sabbath emergency precedent: no one leaves a child (or animal) in a well to observe the Sabbath rest. The emergency overrides the restriction. The man with dropsy is at least as urgent as a child in a well.