Can God hold us accountable for what we are supposed to know is true?
I have two thoughts on this subject:
1. Analogy from speed limits. You have a duty to know where the speed limit changes, especially if you live in the general area. If a speed limit sign is temporarily obscured from view, you are expected to have seen it in the past, or know by other means what the speed limit is (such as from friends familiar with the area or context [neighborhood, school zone, highway, gravel road, etc...], even if the context may include multiple limits, acting upon the lower possibility will eliminate the possibility of being pulled over, while acting on a higher one puts you at risk of being pulled over). You are expected to use these other means until you know for sure.. If you are caught above the speed limit (regardless of reason), you are guilty of acting against the law and should be punished according to the law. If the cop wishes to show mercy, he may by issuing a warning. If the judge wishes to show mercy, he may either cancel the ticket or reduce the fine. Either way, it still stands that you broke the law; however, it is within the power of those who enforce the law to show mercy.
2. Effect of the Emotions. Read the Psychology Class series. I want to focus specifically on the interplay between reasoning and emotion. Emotions always have the power to trump reason and fact to determine what we believe and further, how we act. If we don't like something, it does not change the fact that it is true. We may rationalize our emotional rejection of an illogical conclusion or an inconsistent action. However, no amount of rationalization will make the illogical logical or the inconsistent consistent.We can attempt to rationalize our way "out of" a ticket, but that does not change the fact that we broke the law.
If God does exist, no matter how much we try to rationalize his existence away, it does not change the truth of his existence. Logically sound arguments with premises that are true are used to argue for God's existence. The rejection of the conclusion is based on emotions and bolstered by rationalization. Since the arguments are sound (logic flows correctly and premises are true) the conclusion follows. Since the conclusion follows and we are capable of comprehending it, we CAN be held responsible for accepting or rejecting God's existence (along with other truths) based on what has been revealed to us.
But WILL God hold us responsible? I believe that this can be answered by examining one of our own key desires: justice. This desire has no grounding unless there is a moral law. Theists posit that the moral law comes from God's nature, so He is the only one who knows the moral law perfectly. Since God created man in His own Image, and justice is an inherent desire, it may be posited that justice is part of God. So, it is wise to conclude that God WILL hold us responsible. If God exists, man can and will be held responsible for his knowledge and actions.
Further, since God is the creator of man, He is intimately knowledgeable about each of us. We cannot hide any belief or action from him. All this makes God the only judge who can judge perfectly. Since man is created in God's Image, man possesses innate knowledge that a moral law exists, and he can even comprehend it. This makes man responsible for keeping the moral law. But, man is not capable of keeping the moral law perfectly, so he is responsible to the Judge. As mentioned above, a judge may offer mercy if he wishes. God has provided a way to receive his mercy and avoid the punishment of our moral shortcomings (sin). Jesus Christ died as the punishment for us and bodily rose from the dead to show that He has overcome death. If we believe this (God knows if we are just giving "lip service"), we will receive His mercy. If someone wishes to question if justice is served by someone accepting the punishment for someone else, they need to ask if they are actually thinking of "justice" or simply "revenge".