दाराग्निहोत्रसंयोगं कुरुते योऽग्रजे स्थिते । परिवेत्ता स विज्ञेयः परिवित्तिस्तु पूर्वजः ॥ १७१ ॥
He must be considered as a Parivettri who marries or begins the performance of the Agnihotra before his elder brother, but the latter as a Parivitti.
english translation