There's a lot of wisdom in the world. Not everyone has the verbal acumen to make wise quips that will fit easily on a t-shirt or that will be deemed worthy enough to make an internet quote list. Some folks show their wisdom in how they live their lives. They demonstrate wisdom in the choices they make: how they spend their time; how they treat their bodies; where they work; what they do; how they raise their children; how they spend their money; how they care for the earth; how they regard other people; how they practice their faith; how they deal with hardship; and more.
This question references speaking wisdom, however, not showing wisdom. Still, I think it's worthwhile to acknowledge that that wisdom is all around us. Wisdom doesn't have to be spoken to be wise.
So, with that in mind, I think the wisest thing I've ever heard someone say is something that helped me get through high school. I don't remember the precise moment my mom said it, but I'm sure I was upset about something fairly inconsequential. I had a knack for drama at times. Even though the specifics of the circumstances have escaped me, I still remember how it felt to have that light bulb go off in my head.
"Will it matter in ten years?"
I've heard people say it about their kids - while the days are long, the years are short. So while we may allow ourselves to wallow in the downer times, the truth is that we are really unlikely to remember most any moment, good or bad, with much clarity months and years from now. It's a hard truth to keep in mind when our hearts are hurting, our egos are wounded, or our way seems hidden. But we'll move on. We'll get over it. We'll figure it out.
We're more resilient and forgetful than we give ourselves credit for. It probably won't matter in ten years, at least not in the emotions-laid-raw way that it feels like in the status quo. But we will learn from it, and grow from it. The best thing that we can do is to look for a silver lining and move forward, a bigger person chasing the good. Or at least that's the challenge... I'm still working on it.