On 1st April, people celebrate 'April Fools Day'. People make fool of each other but no one takes it to the heart or files a case against the other person for fooling him. People understand that the action of fooling is not motivated by an evil intention, it is simple fun.
Similarly in God's court of law, only the actions of the mind are considered to be actions. The work performed by the body is not considered to be karma; it does not even result in bondage. That is why Shri Krishna asked Arjun to fight the war with his mind attached in God. If the mind is not attached in the war, it is above dualities of material nature and situated in God. Then Arjun will not reap the fruits of his action because he will not be performing any karma, it is merely acting.