الْكَفّ means holding back. It does not demand abandoning every lawful benefit without reason; it calls for restraint where ethical boundaries would be crossed.
If a contract contains an unclear term, asking for clarification before signing is sensible caution. Refraining from insulting someone in anger is another form of restraint. But refusing to fulfill a real obligation on the pretext “I prefer to do nothing” is not moral scrupulousness.
وَرَع and تَدْبِير work together: thoughtful action and restraint from wrongdoing.