I would like to know the meaning of the sentence below which was created by Leonardo da Vinci:

"Obstacles cannot crush me, every obstacle yields to stern resolve"

Hi Dativo, welcome to the forums..

This is a great phrase which means:

"Obstacles can't stop me, every obstacle (I encounter) falls (yields) due to my decision to stay focused on it. (stern resolve)" 

“Because I don’t give up, nothing is a problem!”