The 4 Steps to Stream-Entry to Nibbâna...
The Blessed Buddha once explained:
Here, householder, the Noble Disciple possesses confirmed confidence and
conviction in the Buddha in exactly his way: Worthy, honourable & perfectly
self-Enlightened is the Buddha! Consummated in knowledge and behaviour,
all transcended, expert in all dimensions, knower of all worlds, unsurpassable
trainer of those who can be tamed, teacher & guide of both gods & humans,
blessed, exalted, awakened & enlightened is the Buddha!
He possesses confirmed confidence in the Dhamma in exactly this way:
Perfectly formulated is this Buddha-Dhamma, visible right here and now,
immediately effective, timeless, inviting each and everyone to come and see
for themselves, inspect, examine and verify. Leading each and everyone
through progress towards perfection. Directly observable, experiencable
and realizable by each intelligence...
He also possesses confirmed confidence in the Noble Sangha in this way:
Perfectly training is this Noble Sangha community of the Buddha's disciples:
Training the right way, the true way, the good way, the direct way!
Therefore do these eight kinds of individuals, the four Noble pairs, deserve
both gifts, self-sacrifice, offerings, hospitality & reverential salutation with
joined palms, since this Noble Sangha community of the Buddha's disciples,
is an unsurpassable & forever unsurpassed Field of Merit, in this world, for
this world, to honour, protect, respect and support ...
He possesses the Pure Morality esteemed by the Noble ones:
Unbroken, untorn, unspotted, unmottled, freeing, praised by the wise,
natural, leading to mental concentration, to absorption...
These are the 4 factors of Stream-Entry that a Noble Disciple possess!
The 4 steps to Stream-entry (sotāpannassa angāni) are therefore obtaining:
1: Unshakable faith in the fact of the perfect Enlightenment of the Buddha.
2: Unshakable faith in the perfect correctness of the true Dhamma.
3: Unshakable faith in the Noble part of the Sangha (monastic+lay).
4: Purified and perfectly unspotted Morality (Sīla).
Canonical references: SN. LV.1; DN. 33; SN. XLVII.8
Not to confuse with the 4 helpers to Stream-entry (sotāpattiyanga):
1: Companionship with great men,
2: Hearing the True Dhamma Law,
3: Wise reflection on Cause and Effect,
4: Living in conformity with the Dhamma.
Canonical references: SN. LV.5; DN.33
More on the Noble Stream-Entry:
Source (edited extract):
The Grouped Sayings of the Buddha. Samyutta Nikāya. Book II 
section 12:41 The five Fears ...
The 4 Steps to Stream-Entry!