"Form is emptiness and emptiness is form" is described in the Heart Sutra. Read "form" as "we" and read "emptiness" as "the whole cosmos". This interdependent relation is applicable to everything in this phenomenal world which has the time and space. Everything is empty of separate existence in this phenomenal world. That's because everything is made of everything else.
This interdependent relation can be easily understood if we look deeply into the relation between light and darkness. Either light or darkness can never be recognized separately. Light and darkness must manifest at the same time in order to be recognized. That's because we can not recognize light without darkness. Meanwhile, we can't also recognize darkness without light.
If we touch the phenomenal world deeply, we can touch another world, namely the noumenal world which has no time and space. If we read "form" as "matter" and we read "emptiness" as "consciousness", "Form is emptiness and emptiness is form" described in the Heart Sutra can be read as "Matter enfolds into consciousness and consciousness unfolds into matter". In other words, matter is inside of consciousness and consciousness is inside of matter. Namely, matter is consciousness and consciousness is matter.
So, protecting the whole cosmos is actually protecting ourselves. And ourselves means body (matter) and consciousness. Therefore, protecting the whole cosmos means protecting our body (matter) and consciousness.