I would prepare a counseling statement that references one or two recent examples of his unwillingness to promptly execute orders, tasks, or directives. Have your chain of command review the counseling statement prior counseling the Soldier. This will ensure that you have support should you have to elevate the situation.
Inform the Soldier that failure to promptly execute an order in a professional manner to the best of his ability, or any whining about the order will be dealt with by refering the matter to the chain of command for resolution up to and including UCMJ action as appropriate. Have the Soldier read his latest set of promotion orders as they relate to obeying orders.
Explain that if he has any questions regarding this counseling he should take the time to review AR 600-20, FM 7-22.7, and the punitive articles of the UCMJ as they relate to a Soldier’s duty to obey the orders of those appointed over him.
Encourage the Soldier to continue reading regulations to better himself professionally but not for the purpose of causing friction or avoiding work. Make it clear that you do not want to stifle initiative and feedback, but when an order is given you expect it to be followed. Finish the counsleing statement with the standard derogatory statement.
Read The Mentor: Everything you need to know about leadership and counseling for more information about Counseling, Leadership, Corrective Training, and Separations in the Army.