According to the Larger Sukhavativyuha Sutra, Amida Buddha as a bodhisattva (Dharmakara) made 48 Vows which express the bodhisattva's aspirations and goals. Honen and Shinran (of Japan) focused on the 18th Vow and considered it to be primal. Hence, in the Pure Land Tradition, this vow is often referred to as the Primal Vow.

It reads: If, when I attain Buddhahood, the sentient beings of the ten quarters, with sincere mind entrusting themselves, aspiring to be born in my

Land, and saying my Name perhaps even ten times, should not be born there, may I not attain the supreme enlightenment. Excluded are those who commit the five grave offences and those who slander the right dharma.

In the lineage of (Tanluan, Taochao &) Shantao of China, the "Nembutsu" is interpreted as the "saying of Amida Buddha's Name. Today, most commonly "Namo-Amida-Butsu." The essence of the Vow is that through the sincere recitation of the Buddha's Name we are assured birth in the Pure Land of Amida Buddha as promised in the 18th Vow. The Pure Land is in essence Nirvana in a shape or form, a reality brought forth by the Vow Power of Amida Buddha. Shinran's view of the Vow is unique in that he experienced the "with sincere mind entrusting themselves, aspiring to be born in my Land," as coming from the side of the Buddha itself. In other words, it is not the mind of the unenlightened saying "I with sincere mind, entrust myself (to the Buddha) and aspire for birth in the Pure Land" but rather it is the sincere, joyful heart and mind of the Buddha itself which has been transferred to that individual and because of it that individual now wishes for birth in the Pure Land in concord with the Buddha's ultimate aspiration that all beings aspire for birth in the Pure Land of Enlightenment. While it is the individual that says the Name, Namo-Amida-Butsu, ultimately it stems from the great heart and mind of the Buddha. The last part of the Eighteenth Vow has a special significance in the Shin Buddhist Tradition in that it is not seen as an exclusionary clause. Rather the clause is interpreted "as an expression of compassion so boundless and profound that it directs itself to the very person whom it censures-the being who has committed the five grave offenses and slandered the dharma."