AN 4.179
PTS: A ii 167
Nibbana Sutta: Unbinding
translated from the Pali by
Thanissaro Bhikkhu

Then Ven. Ananda went to Ven. Sariputta and, on arrival, exchanged courteous greetings with him. After an exchange of friendly greetings & courtesies, he sat to one side. As he was sitting there, he said to Ven. Sariputta, "Friend Sariputta, what is the cause, what is the reason, why some beings do not become totally unbound in the present life?"

"There's the case, friend Ananda, where beings do not discern, as it actually is present, that 'This perception has a share in decline'; 'This perception has a share in stability'; 'This perception has a share in distinction'; 'This perception has a share in penetration.' [1] This is the cause, this is the reason, why some beings do not become totally unbound in the present life."

"And what, friend Sariputta, is the cause, what is the reason, why some beings do become totally unbound in the present life?"

"There's the case, friend Ananda, where beings discern, as it actually is present, that 'This perception has a share in decline'; 'This perception has a share in stability'; 'This perception has a share in distinction'; 'This perception has a share in penetration.' This is the cause, this is the reason, why some beings become totally unbound in the present life."

Note

1.
A perception with a share in decline is one that causes the mind to fall from concentration. A perception with a share in stability is one that helps to maintain concentration. A perception with a share in distinction is one that leads to higher stages of concentration. A perception with a share in penetration is one leading to liberating insight.