DEUT771 From "the seventh year," do I not know that it is the year of shemitah? Why, then, need this be written? To teach that there is another "shemitah" [release] similar to this. And which is that? One who lends his neighbor without specifying a date for repayment, in which instance he is not permitted to claim it in less than thirty days, the master having ruled: thirty days in a year is considered "a year" (Makkoth 3b)