For the method of godliness consists of these two things: pious doctrines and virtuous practice;
neither are the doctrines acceptable to God apart from good works,
nor does God accept the works which are not perfected with pious doctrines...
A most precious possession therefore is the knowledge of doctrines;
also there is need of a wakeful soul, since there are many that
make spoil through philosophy and vain deceit...
concerning all of whom together the Lord says, Take heed lest any man mislead you.
— St. Cyril of Jerusalem