The problem is people don't always know their own strength.

He did not know his own strength in the least.

I know your strength as no one else knows it.

Now, only in my time, have you known your full strength.

It is not just that some people don't know their own strength.

We know your strength - if one may call it by that name.

The electronic media were young, too, and did not know their own strength yet.

They were the ones, after all, who knew their own strengths.

Now here's a definite case of a boy who doesn't know his own strength!

At the conclusion he said, 'Now they know our strength.