The Torah talks about four different types of watchmen. Some as a favor will watch something for a friend. Another type will get paid for watching an article. A third type is someone who rents an item to use and is responsible to watch it from any harm. A fourth type is one who borrows an object from his neighbor and is liable for any damage that befalls it.
In every case there is a different responsibility for damage that occurs. Nevertheless, in each case where the caretaker is exempt from reimbursing the owner, he must go to court and verify that he was not negligent in watching the item.
The language the Torah uses to express this obligation is: וְנִקְרַב בַּעַל הַבַּיִת אֶל הָאֱלֹהִים, and the ‘watchman’ shall approach the court…”, that he has not laid his hand upon his fellow’s property. (Ex. 22,7)
A Rabbi once used this passage to express a different notion. Explaining the passage literally, he said if a person wants to approach or come close to Hashem, he must demonstrate that he has not injured his fellow man either materially or mentally. We often do things and unintentionally hurt someone either financially or emotionally. To be a righteous individual we must ever be mindful not to harm someone, even unintentionally.