Heidegger first gives his translation of Heraclitus fragment 53.
Between x and y, aparting and gathering, the De-cision, Dissociating Exposition (Mindfulness, 15).Confrontation [πόλεμος, polemos] is indeed for all (that comes to presence) the sire (who lets emerge), but (also) for all the preserver that holds sway. For it lets some appear as gods, others as human beings, some it produces (sets forth) as slaves, but others as the free.The polemos named here is a strife that holds sway before everything divine and human, not war in the human sense. As Heraclitus thinks it, struggle first and foremost allows position and status and rank to establish themselves in coming to presence. In such a stepping apart, clefts, intervals, distances, and joints open themselves up. In con-frontation [Aus-einandersetzung], world comes to be. Confrontation does not divide unity, much less destroy it. It builds unity; it is the gathering (logos). Polemos and logos are the same.
I don't think the sway in the passage is the wesen sway, of Contributions and Mindfulness, but "holds sways" as in prevails.