This teaching is from the section The Planes of Realization from “In the Buddha’s Words” by Bhikkhu Bodhi.

Thus have I heard. At one time, the Blessed One was residing in Kosambi at Ghosita’s park. There, the Blessed One addressed the bhikkhus: “Is there a method, bhikkhus, by which a trainee bhikkhu, standing on the plane of a trainee, can understand: ‘I am a trainee,’ and an arahant bhikkhu, standing on the plane of an arahant, can understand: ‘I am an arahant’?”

The bhikkhus replied, “Our teachings are rooted in the Blessed One, venerable sir, guided by the Blessed One, and have the Blessed One as their refuge. It would be good, venerable sir, if the Blessed One himself would clarify the meaning of this statement.”

The Blessed One said: "There is indeed a method, bhikkhus, by which a trainee bhikkhu, standing on the plane of a trainee, can understand: ‘I am a trainee,’ and an arahant bhikkhu, standing on the plane of an arahant, can understand: ‘I am an arahant’.

What is the method, bhikkhus, by which a trainee bhikkhu, standing on the plane of a trainee, understands: ‘I am a trainee’?

  1. Here, bhikkhus, a trainee bhikkhu understands as it truly is: ‘This is suffering,’ ‘This is the origin of suffering,’ ‘This is the cessation of suffering,’ and ‘This is the path leading to the cessation of suffering.’ This too, bhikkhus, is a method by which a trainee bhikkhu, standing on the plane of a trainee, understands: ‘I am a trainee.’

  2. Furthermore, bhikkhus, a trainee bhikkhu reflects thus: ‘Is there any other ascetic or brahmin outside this teaching who teaches a doctrine so true and factual as the Blessed One?’ He understands thus: ‘There is no other ascetic or brahmin outside this teaching who teaches a doctrine so true and factual as the Blessed One.’ This too, bhikkhus, is a method by which a trainee bhikkhu, standing on the plane of a trainee, understands: ‘I am a trainee.’"

  3. Furthermore, bhikkhus, a trainee bhikkhu understands the five faculties: the faculty of confidence (faith), the faculty of persistence (energy), the faculty of mindfulness, the faculty of collectedness (concentration), and the faculty of wisdom. He knows their tendencies, highest points, fruits, and final goals. He does not experience them with the body but sees them clearly with wisdom. This too, bhikkhus, is a method by which a trainee bhikkhu, standing on the plane of a trainee, understands: ‘I am a trainee.’

  4. What is the method, bhikkhus, by which an arahant bhikkhu, standing on the plane of an arahant, understands: ‘I am an arahant’? Here, bhikkhus, an arahant bhikkhu understands the five faculties: the faculty of confidence, the faculty of persistence, the faculty of mindfulness, the faculty of collectedness, and the faculty of wisdom. He knows their tendencies, highest points, fruits, and final goals. He experiences them with the body and sees them clearly with wisdom. This too, bhikkhus, is a method by which an arahant bhikkhu, standing on the plane of an arahant, understands: ‘I am an arahant.’

  5. Furthermore, bhikkhus, an arahant bhikkhu understands the six faculties: the eye faculty, the ear faculty, the nose faculty, the tongue faculty, the body faculty, and the mind faculty. He knows that these six faculties will cease entirely and no new faculties will arise anywhere. This too, bhikkhus, is a method by which an arahant bhikkhu, standing on the plane of an arahant, understands: ‘I am an arahant.’"

Trainee here is a reference to someone who is a stream-enterer but not an Arahant. The Buddha is sharing this teaching to help an individual see where they’re on the path.

Related Teachings:

Entering the Fixed Course of Rightness (SN 25.1) - The Buddha is sharing here that an individual who has faith in his teachings or has cultivated a degree of wisdom through reflecting on the teachings with close examination would not die without attaining to stream-entry. There are also additional notes that can help understand what teachings a stream-enterer would’ve verified and the way of practice that leads to stream-entry.

Eight Persons Worth of Gifts (AN 8.59) - The Buddha is sharing in this teaching that it is very beneficial to be associated with individuals that are enlightened or practicing to attain enlightenment. The additional notes explain how the presence of fetters relate to the different stages of enlightenment.

Way of Practice to eradicate the conceit “I Am” (SN 22.89) - Venerable Khemaka is ill, and some elder bhikkhus ask Dāsaka to convey their concern to him. A series of exchanges ensue, mediated by Dāsaka, until Khemaka, despite his illness, goes to see the elder bhikkhus himself. The elders inquire about his understanding of the Dhamma. Khemaka explains that while he does not identify any of the five aggregates (form, feeling, perception, formations, and consciousness) as self, he still experiences a subtle “I am” conceit associated with these aggregates. He likens this to the lingering scent on a cleaned cloth, which eventually fades away.