Yesterday is history. Tomorrow is a mystery. Today is a gift. That's why it's called the present.
Alice Morse Earle
Although I've attributed this quote to American historian and author Alice Morse Earle, it's also renowned as Master Oogway's advice to Po. (Click on the underlined link to watch a short video clip from Kung Fu Panda.)
Genesis 1:14-19 explains God spent pretty much the entire fourth day of creation setting up a system of lights in the sky to help us mark the days. So doesn't it follow the idea of days must be a fairly important concept?
We can think of days as the basic time units of our lives. Each day is one thin slice of the loaf of bread that makes up our lives. (The bread of life! Get it? Hmm. No, upon further review, I agree with you. That one's terrible.)
If we were to live to be 100, we would have 36,525 units of life. That includes 25 leap days. (Some people say we're living in the end times. If so, believers may get raptured into eternity before they're chronologically 100 years old, but what're you gonna do, am I right?)
Regardless how many units of life you get, do your best to make each unit count. You'll never get to live it again. Don’t waste time—ha, literally—with regrets about yesterday or worries about tomorrow.
Think about it, my dude: if you knew today was going to be your last day on earth would you act differently? What would be your priorities? How would you treat others on this day? As much as you can, live all your todays as if they are the last one you will have.