"Being and time determine each other reciprocally, but in such a manner that neither can the former - Being - be addressed as something temporal nor can the latter - time - be addressed as a being"

In this quote, Heidegger is asserting that being (existence) and time are synergistic and impact each other in an equally causal relationship. Nevertheless, he likewise keeps in mind that being can not be considered something that exists within a temporal structure, nor can time be considered a remaining in itself. Basically, he is highlighting the inseparability of these 2 concepts while likewise complicating their ontological status.