I have to agree with @GentlePurpleRain's shorter and more elegant answer.
The best way to protect your child from feeling guilt is to avoid teaching him any moral standards, i.e. don't teach him the difference between good and evil, and don't teach him self-reflection or self-evaluation.
Guilt is a natural result of going against one's morals. It promotes prosocial behavior (good for everyone.) Guilt shows a sensitivity to the feelings of others. People behave well to avoid feeling guilt, and feel guilt when they do something that hurts someone, and makes them feel remorseful. It is a moral emotion.
Imagine a person who doesn't feel guilt. One such person can do a lot of harm to a lot of people, depending on how significant their lack of empathy is.
Moral standards represent an individual’s knowledge and internalization of moral norms and conventions. People’s moral standards are dictated in part by universal moral laws, and in part by culturally specific proscriptions. ...[T]here is broad social consensus that such behaviors are “wrong” (e.g., interpersonal violence, criminal behavior, lying, cheating, stealing).
The morally relevant "negative" emotions are shame, guilt, and embarrassment. Several positive moral emotions are elevation, gratitude, the morally relevant experience of pride, and empathy.
As the self reflects upon the self, moral self-conscious emotions provide immediate punishment (or reinforcement) of behavior. In effect, shame, guilt, embarrassment, and pride function as an emotional moral barometer... When we “do the right thing,” positive feelings of pride and self-approval are likely to result.
If we accept that guilt is normal and even good, then why does it get such a bad reputation? Probably because many people use guilt and shame synonymously. One possible difference between them is that
when describing shame-inducing situations, respondents expressed more concern with others’ evaluations of the self. In contrast, when describing guilt experiences, respondents were more concerned with their effect on others. This difference in “egocentric” versus “other-oriented” concerns isn’t surprising given that shame involves a focus on the self, whereas guilt relates to a specific behavior.
Shame is considered more painful because one’s core self is at stake, threatened by feelings of worthlessness, powerlessness, and exposure (whether real of imagined.)
Guilt, of the other hand, is less painful because the feeling is focused on a specific behavior, not the self. Rather than needing to defend one’s self, people feeling guilt consider their behavior and its consequences. Guilt is more adaptive and beneficial than shame. Guilt leads to apologies and attempts at restoration. Shame leads to separation and denial.
What you might want to do is help your child deal with shame, not guilt. But that is a different question.
Guilt and Children
Moral Emotions and Moral Behavior