Ja 300 The Story about the Wolf

In the present while the Buddha is on retreat he gives leave for those who practice the austerities to visit him. Monks would dress up in old robes to get the privilege, and then throw the robes away afterwards. The Buddha told a story about a wolf who decided to keep the Uposatha precepts, including non-killing, until he saw a goat and then gave up on his austerity.

1. Parapāṇarodhā jīvanto, maṁsalohitabhojano,
Vako vataṁ samādāya, upapajji Uposathaṁ.

Living by killing other beings, feeding on their flesh and blood, the wolf undertaking a vow, established the Uposatha vow.

2. Tassa Sakko vataññāya, ajarūpenupāgami,
Vītatapo ajjhappatto bhañji lohitapo tapaṁ.

Sakka, understanding his vow, approached in the form of a goat, impenitent, fallen, the blood-drinker broke his austerity.

3. Evam-eva {2.451} idhekacce samādānamhi dubbalā,
Lahuṁ karonti attānaṁ vako va ajakāraṇā ti.

So some feeble people here in the world, in their undertaking, quickly make themselves give up like the wolf did because of the goat.

In this connection, established the Uposatha vow means undertook to keep the Uposatha.

Understanding his vow means understanding his weak vow.

Impenitent, fallen means having given up his penance he had undertook, he sprang forward to eat it, this is the meaning.

Blood-drinker means blood-sucker.

Austerity means he broke the austerity he had undertaken.