क्षत्रं प्राणो वै क्षत्रं प्राणो हि वै क्षत्रंत्रायते हैनं प्राणः क्षणितोः प्र क्षत्रमत्र-माप्नोति क्षत्रस्य सायुज्यं सलोकतांजयति य एवं वेद ॥ ४ ॥
In plain words
Kṣatra — that ruling power — is simply your own breath. Your breath truly is that power, again and again the point is made. It is your breath that shields you from being wounded. Know this, and you claim the highest form of that power, one nothing can touch — and you come to share its very world, its very presence, completely.
Close to the Sanskrit
Ruling power — the breath, indeed, is ruling power; the breath, indeed, verily, is ruling power. The breath protects him from injury. He attains the foremost, unassailable ruling power. He wins union and co-residence with ruling power, he who thus knows.