यदा वा ऋचमाप्नोत्योमित्येवातिस्वर-त्येव५ सामैव यजुरेष उ स्वरो यदेतदक्ष-रमेतदमृतमभय तत्प्रविश्य देवा अमृताअभया अभवन् ॥ ४ ॥
In plain words
When a seeker reaches the Ṛc and chants aloud with 'Om', that very sound is the Sāman, the Yajus, the vital tone. It is this imperishable syllable, immortal and free from fear. Entering it, the gods themselves became immortal and fearless.
Close to the Sanskrit
When indeed one reaches the Ṛc, chanting aloud precisely with 'Om', the Sāman itself, the Yajus, this verily is the tone, which is this imperishable, this immortal, fearless one; having entered that, the gods became immortal and fearless.