Mantra 4

तद्यदृक्तो रिष्येद्भूः स्वाहेति गार्हपत्ये जुहुयादृचामेव तद्रसेनर्चां वीर्येणर्चां यज्ञस्य विरिष्टं संदधाति ॥ ४.१७.४ ॥

In plain words

Therefore, if the sacrifice is harmed on the side of the Ṛc, let him offer in the householder's fire with "bhūḥ, svāhā." Thus by the very essence of the verses of the Ṛc, by their strength, he mends the harm done to the sacrifice on the side of the Ṛc.