When many people think about grammar they usually think about tedious rules or the ongoing contemporary debate that there are are no rules when it comes to grammar as this is a Medieval European construct. The latter group is sometimes difficult to read as they insist on practicing what they preach. For those in the Classical school tradition they realize that grammar is "the first of the arts to assist those who are aspiring to increase in wisdom." (John of Salisbury)
Already there is a monumental difference between most up-to-date views of grammar and the traditional way. Grammar is a means toward an end. The ultimate end of grammar is not to be able to read, write, and speak without sounding like a vandal, it is so that one may ultimately become wise.
"Grammar is the science which teaches us to explain the poets and historians; it is the art which qualifies us to write and speak correctly. Grammar is the source and foundation of the liberal arts." (Rhabanus Maurus)