what is the effect of the juxtation of 'passion' and the 'lifeless'? what is shelley suggesting about human ambition?

The statue is of course lifeless..... it's nothing more than fragments strewn across the ground. But the passion endowed on the face remains and can be seen.... the frown or sneer on the ruler's face speaks to his power. The "life things" have a life all of their own, frozen in marble.