He paid tribute to members of the Armed Forces who have served in Afghanistan, saying that they had brought "liberty to those made captive by terror and oppressed by an ideology which masquerades as religion".
Dr Sentamu went on to say that the military covenant had "come under strain" in recent months and spoke of the special relationship between the Armed Forces and the nation, saying that the country owed a debt to those willing to make the "ultimate sacrifice".
"In this country there has always existed a special relationship between the Armed Forces and this country which they represent," he said.
"Soldiers will be called upon to make personal sacrifices - including the ultimate sacrifice - in the name and service of the Crown.
"In return for putting the needs of the nation before their own, and for being ready to make the ultimate sacrifice, members of our armed forces should always expect just treatment and respect by Her Majesty's Government and by us all.
"They have a right to believe that they and their families will be sustained and rewarded by commensurate terms and conditions of service."
Dr Sentamu visited Afghanistan in 2005 and last year raised more than £100,000 for soldiers serving there and their families in a sponsored parachute jump.