Why is doctrine more foundational than experience?
Doctrine is foundational because without it you have nothing; experience, though good, does not set your feet in concrete. Doctrine—the teaching—is primary, providing stability that experience alone cannot, and Paul defended it against false teaching in Galatians, so the believer must be grounded in it.
Les explains that in Galatians Paul is not so much defending his person as he is his doctrine. Doctrine is a word not to be used loosely, though in our day it has largely gone by the boards. If you do not have doctrine, you have nothing. Today there is much emphasis on experience, and that is all well and good, but experience does not set your feet in concrete. It takes doctrine, the primary word, the teaching. Paul was refuting false doctrine that had crept into the Galatian churches and every church he founded. This problem is not unique to Paul's day; it has plagued Christianity through the centuries and is just as relevant today, as believers still fight the subtle false teaching of legalism in all its shapes and forms.