Some of the wise people said, The days are three types:
Yesterday: It is like a moral lesson, so it remains as an admonition and a lesson for you.
Today: It is like a friend who gives you [good] advice. You did not approach it, rather it came to you. It was hidden from you for a prolonged period and will depart quickly, so get hold of it [by doing good].
Tomorrow: As for tomorrow, you do not know what Allaah has decreed, whether you’ll be from its people or not.