This short hidden phrase tells you just where it's found
Left right the first phase and it then turns around.
Each character's vital, the order is too.
Don't skip past the title: it's also a clue.
If you've gone to great lengths and it still seems unfair,
It's simply the _ that you find in a _.
Oppose when life flows go on forward and woes act as tos or fros
Hint:
Well, I'm not an exponent of hinting too much
But there is a component of wordplay and such
So with "strengths" and with "pair" fill the blanks and you'll see
(If you're clever) just where the solution must be.
The answer's a phrase that's just three words long. I thought it was simple, I guess I was wrong. The pattern goes right and then it goes left. The two fit together, I thought that was deft. All blanks count as letters in my little rhyme. I'm sure you'll discover the message in time.
Addendum:
Where is the sandbox when you need it? So, when I looked at this with fresh eyes I figured my attitude toward punctuation was not reasonable. Also, there was an out-and-out error. I've rewritten for the same phrase with the same scheme but without punctuation. Feel free to down vote. I would but I'm not allowed. As always, happy puzzling.