It is to clearly recognize when something is an illusion and when it is reality.
It is only because we have become convinced that illusions are real, that they have truth to them, and give them credit, that we are experiencing sleep.
Unconsciousness is denial, which is an attempt to not be aware of the factual truth, the whole truth, and nothing but the truth.
Instead we have attempted to block the truth, so that we might have an opportunity to believe that something else is the truth, without the real truth distracting us or reminding us of what the truth is.
We had to hide from God, which seems like hiding God, in order to be as close as possible to forgetting the truth. Otherwise we could not possibly give even a moment's attention to illusions which are unreal.
We wouldn't be able to even potentially believe illusions are truth while the real truth was glaringly obvious, but with the real truth out of sight, illusions appear to be plausible.
Unawareness of the real truth makes it "easier" to believe in an illusion of truth. The purpose of the illusion then is to hide the real truth and substitute for it, replacing it with some other form of meaning.
Even though spiritual lessons may show up in a variety of forms and feature different people and problems, they are all still basically the same one lesson. They are all exercises in learning what is true and what is false. Learning to recognize an illusion for what it is, rather than make it real and react to it.
When we believe an illusion has truth to it, we will have a whole cascade of reactions and counter-perceptions which arise out of that fundamental sense of reality. We might think our lesson is to deal with those reactions or overcome them, but ultimately the lesson is only learning to "see through" the illusion.
To overlook the claim of an illusion and not see it as the truth, to not believe in it, and to not fall for its tricks, is simply an act of forgiveness. Forgiveness is therefore the answer to all lessons. To put it even more clearly, forgiveness is the ONLY answer to ALL problems. It is not one of many options, it is the only option.
To remain deluded is unforgiveness, judgement, and attack. To forgive is to learn to see clearly what the truth is, which will put everything into its proper perspective and show the illusion for what it is. When the truth is present, there is so much obvious evidence that the illusion is false, you can't help but recognize it as false. It's obvious, without any particular effort or skill needed to see it as such.
Forgiveness isn't an interpretation of illusions. It's not an attempt to twist your way of looking or to strain or make effort to see in a certain way. Forgiveness is completely effortless and natural. It looks upon illusions in stillness, doing nothing, and simply recognizing them for what they are. They are false. They are untrue. They are not reality.
This is how simple it all comes down to. Every lesson is a lesson in forgiveness. Every lesson presents illusions which you initially believe are true, are dangerous, are able to affect you, or prove that God is dead. Learning to sort out the evidence and become aware of a greater truth is the only way out of the lesson. Learning to discern true from false.
All lessons are learned the same way. Once forgiveness has come to establish a clear perception - true perception - of what the truth really is and what is false, the lesson is over, and the need for the lesson is over. Forgiveness is a permanent correction of sight.
To forgive or not to forgive, that is the question. Forgiveness is the answer.