What does one do if he errs in his prayer out of ignorance?

Question:
If a person prays and errs in his prayer out of ignorance?

Answer:
If there is an error in it that invalidates it, he repeats it. If it does not invalidate it, he is taught and does not repeat it. If he neglected a pillar, such as tranquility or something else, he repeats it and is taught, just as the Prophet (peace and blessings be upon him) ordered that it be repeated. If it is merely that he neglected some of the recommended practices that do not invalidate it, then it does no harm; he is taught perfection, and it does no harm.
Q: If he neglected only one pillar?
The Shaykh: He is taught and repeats it.