Upakāro ca yo mitto,
sukhe dukkhe ca yo sakhā,
atthakkhāyī ca yo mitto,
yo ca mittānukampako —
etepi mitte cattāro iti viññāya paṇḍito
sakkaccaṃ payirupāseyya
mātā puttaṃ va orasaṃ.

The friend who is a helpmate,
the friend in happiness and woe,
the friend who gives good counsel,
the friend who sympathises too —
these four as friends the wise behold
and cherish them devotedly
as does a mother her own child.

Dīgha Nikāya 3.265

Everyman’s Ethics: Four Discourses by the Buddha (WH 14),
translated by Narada Thera