Within the dream we are dreaming, A Course in Miracles (ACIM) is clear that we have a safety net. We seldom see it that way as we feel trapped in a world of our making with no way out. Fear and guilt overwhelm us and we look to the words of the Course to elicit feelings of safety while completely misunderstanding where to find safety. The ego uses the reminders of the Truth from the Course so that we end up quoting them to ourselves and each other in an effort to feel good, prove we're right and ultimately safe in a world of terror. This approach is an ego tick that negates the practice of true forgiveness.
When we're willing recognize this world is not a happy place and we don't feel safe, our justifications with the ego get called into question during the practice of forgiveness. We find we're literally junkies who are addicted to excuses for what we're choosing with the ego; and since the ego cannot allow forgiveness to reveal any ego trick, justification is a defense. Remember, a defense does what it says, i.e., it defends (protects) and only what is weak uses defense due to the fear of lack or loss.
A reminder does what it says, i.e., it reminds or points the way to something else in the mind. Reminders of the Truth from the Course point away from belief with the ego and towards (the meaning of) the Truth. This is a course on the practical application of forgiveness and the experience of the meaning of the Truth. It is not a course on belief and justification. The choice is yours in how you will use the Course.
A common example that most Course students recognize is regarding anger. Nowhere in the Course are we told we shouldn't get angry. That would actually be unrealistic. We are simply told not to deny we're angry and to admit we are choosing to get angry. However, what we are told is not to justify the anger. Don't make excuses for why you are angry. It's never for the "justification" reasons you think.
Taking this basic concept, let's look into the ego trick of justification as a defense to keep the ego safe which we mistakenly believe is our safety. Once you understand the trick, it can be applied to undoing anything with the ego. In this article, we're going to expose the trick using the reminders of the Truth from the Course as those are also subject to justification.
Belief, Justification, Assurance and Defense
What makes it so difficult to recognize the ego is using justification with reminders of the Truth is because they seem so wonderful and thus we want to believe them. They sound like the Holy Spirit is telling us they are true when it's really the ego tricking us into believing they are true. It comes down to the difference between a defense of the ego and a reminder from the Holy Spirit and the choice you make. There is a huge difference in the mind.
First, let's look at few basic concepts to further the discussion:
Belief
Choosing to believe in an unreal ego idea (thought) makes it appear real and so you only have to invest belief with the unreal to prove you are right. Continued belief (judgment) keeps the idea with you.
Justification
Justification means, "to show, prove or declare something is right." It is the reasoning used by the ego for believing the unreal idea.
Defense
Since all belief and justification is in the mind, defense is in the mind and it means, "an attempt to justify (prove correct) or to do something in favor of an action." The only action you can take in the mind is decision making. Choosing to justify a ego belief makes a defense. It protects the unreal belief as you're in total agreement with the ego and denial of the Truth.
Let's be really clear: The defense (belief plus justification) does not make what you are attempting to believe true. It makes the belief (unreal) appear real. The meaning is still what you've chosen with the ego even when used to justify a reminder of the Truth.
Assurance
Assurance means, "to dispel doubts or a promise." There are two types of assurances: God or ego. The only assurances the ego provides is what you're already experiencing and is clearly not working. Reminders of the Truth (God) point directly to the assurance (promise) of what is real. You choose which one sounds better and if it is the reminder, then you've got to get out of the justification trick.
The Separation Never Happened
We wouldn't believe we're in this world unless we'd already bought into the idea that we've separated from God. "The separation never happened" is the basic Truth reminder as part of the Atonement in the Course. It does, however, acim
 used by the ego as a defense to negate the practice of forgiveness.
Justification of the reminder is the ego defense strategy. If we rephrase "the separation never happened" to the ego version, the trick of justification begins to expose itself: "Because the separation never happen, as the Course says, you are justified and correct to believe it didn't happen." Honestly looking reveals that we just explained why our belief that "the separation never happened" is correct using our "because" excuse (justification) with the ego. Again, this is not a Course on belief or justification as that furthers the ego and hides what the Truth reminder is pointing towards (which in this case is part of the Atonement, the solution). One mistaken belief leads to the next. Not far behind are the justifications as to "why" you are safe and still at home with God (other Truth reminders) in this world.
The Safety Net
Remember, this is a course in the obvious. The safety net cannot be found in belief which defends the ego. It is only in those reminders of the Truth in the Course. Those do not require belief. Truth is not an idea. It's reality.
All reminders of the Truth, which are so lovingly pointed out to us in the Course, are there to do exactly what a reminder does: Remind us that we have reality (Truth) to catch us if we make a different choice. This does not mean to choose to "bliss out" on these assurances through ego belief. Rather, it means to consider them the explanations for why it is safe to practice forgiveness and get the experience of the Truth (which needs no defense).
Consider the rest of the Course another set of loving explanations for what you are choosing to give up (forgive). The light of Love shines brightly enough for the safety net to be obvious to anyone willing to look at their ego and forgive.
Defenselessness
To the ego, defenselessness is seen as weakness and yet to see the safety net, you will need to stop defending the ego. The justification junkies we all are is merely a mind addiction from wanting to be right instead of happy. However, now you know that justification of belief merely defends the ego; and now you have the trick exposed to apply to anything in your life.
Defenselessness (not defending the ego) is true strength because it relies on the Father where the Truth reminders point to remembrance of Him. To head in that direction in the mind, you must first accept that you've already chosen with the ego and will continue to do so as you learn forgiveness. You are going to get upset and angry. Don't defend (justify) that anger. Also, accept that you've been trying to believe your way to the Truth instead of practicing forgiveness of the beliefs (judgments) which leads directly to where the reminders point. Don't defend (justify) the trick even if you feel guilty or angry (don't justify them). Every time you accept responsibility for anything as being your choice, even when you've chosen to believe with the ego, you have the ability to choose differently because you are not justifying it which defending the ego.