No one knows what he can do till he tries
You don't know what you can do until you try.
It is sometimes expedient to forget what you know.
No one know what he can do till he tries.
No one knows what it is that he can do until he tries.
Necessity knows no law except to conquer.
He can best avoid a snare who knows how to set one.
Would you be known by everybody? Then you know nobody.