신명기 15:14의 Quotation

If you heed the old, etc. I.e., if you review what you already learned, then you will gain wisdom from it and understand new matters from the old. Rashi explains likewise in Succah (46b). Even though regarding [the seeming redundancy] הענק תענק (surely bestow a gift) we say that the Torah uses common speech, we expound the verse whenever we are able to (Re”m). Alternatively, here the word והיה (lit., it will be) is an expression of certainty, whereas the word אם (if) is an expression of doubt. Therefore, the verse is expounded.