What four? It’s when a noble disciple has experiential confidence in the Buddha … the teaching … the Saṅgha … And they have the ethical conduct loved by the noble ones … leading to immersion. People have to possess these four things in order for the Buddha to declare that they’re a stream-enterer, not liable to be reborn in the underworld, assured, destined for awakening.”

Linked Discourses 55.5 1. At Bamboo Gate With Sāriputta (2nd)

Then Sāriputta went up to the Buddha, bowed, and sat down to one side. The Buddha said to him: “Sāriputta, they speak of a ‘factor for stream-entry’. What is a factor for stream-entry?” “Sir, the factors for stream-entry are associating with true persons, listening to the true teaching, rational application of mind, and practicing in line with the teaching.” “Good, good, Sāriputta! For the factors for stream-entry are associating with true persons, listening to the true teaching, rational application of mind, and practicing in line with the teaching.