Manusmriti

siva.sh/manusmriti/2/84

क्षरन्ति सर्वा वैदिक्यो जुहोतियजतिक्रियाः । अक्षरं दुष्करं ज्ञेयं ब्रह्म चैव प्रजापतिः ॥ ८४ ॥

sanskrit

All rites ordained in the Veda, burnt oblations and (other) sacrifices, pass away; but know that the syllable (Om) is imperishable, and (it is) Brahman, (and) the Lord of creatures (Pragapati).

english translation

kSaranti sarvA vaidikyo juhotiyajatikriyAH | akSaraM duSkaraM jJeyaM brahma caiva prajApatiH || 84 ||

hk transliteration by Sanscript