Biden and Gates were together for the change of command ceremony in Baghdad in September 2010.
"I want to thank my friend Secretary Gates, for his unique willingness to serve two presidents of different parties with differing views. A testimony to Bob's patriotism, his commitment to service and above all his determination to lead this effort through. He deserves your applause," Biden said during his speech. "To excuse the personal reference, as we used to say in the Senate, 'This is one good man'."