Brahma Sutras
ॐ अग्निहोत्रादि तु तत्कार्यायैव तद्दर्शनात् ॐ ॥ ४-१-१६॥
But Agnihotra etc., conduce to the very same result, for so it is revealed (in the Upanishads).
english translation
OM agnihotrAdi tu tatkAryAyaiva taddarzanAt OM ॥ 4-1-16॥
hk transliteration by Sanscript