There is nothing that it is better to commit to memory than those kinds of words and phrases whose meaning we do not know, so that where we happen to meet either with a more learned man of whom we can inquire, or with a passage that shows, either by the preceding or succeeding context, or by both, the force and significance of the phrase we are ignorant of, we can easily by the help of our memory turn our attention to the matter and learn all about it.
St. Augustine, On Christian Teaching
What To Memorize
Christian Leithart 