a chain is only as strong as its weakest link

A chain is only as strong as its weakest link is referring to the weakest link in a group of people which can then bring the entire group or organization down. In business, it is used in reference to an organization only being as strong as their weakest member. The cliche began as the literal meaning of a chain only working as good as the weakest link within it since a weak link will make the entire chain faulty.