The Institute of Internal Auditors defines internal auditing as: “an independent, objective, assurance and consulting activity designed to add value and improve an organization's operations. It helps an organization accomplish its objectives by bringing a systematic, disciplined approach to evaluate and improve effectiveness of risk management, control, and governance processes."
The definition clarifies Internal Auditing as an Assurance and Consulting Activity. Therefore the person giving the assurance must be independent and objective as well. He should also be knowledgeable in the operation of the organization so that he can be trusted with the job of a consultant.