Because:

when you honor
-- as the devas, Indra --
one from whom
you might learn the Dhamma,
he, learned, honored,
confident in you,
    shows you the Dhamma.

    You, enlightened, heedful,
befriending a teacher like that,
    practicing the Dhamma in line with the Dhamma,
    pondering,
    giving it priority,
become
    knowledgeable,
    clear-minded,
    wise.

But if you consort with a piddling fool
who's    envious,
    hasn't come to the goal,
you'll go to death
without    having cleared up the Dhamma right here,
with    your doubts unresolved.

Like a man gone down to a river --
turbulent, flooding, swift-flowing --
and swept away in the current:
    how can he help others across?

Even so:
he who hasn't
    cleared up the Dhamma,
    attended to the meaning
        of what the learned say,
    crossed over his doubts:
how can he get others
to comprehend?

But as one who's embarked
    on a sturdy boat,
    with rudder & oars,
would -- mindful, skillful,
knowing the needed techniques --
    carry many others across,

even so
an attainer-of-knowledge, learned,
self-developed, unwavering
can get other people to comprehend --
    if they're willing to listen,
    ready to learn.

    So:
you should befriend
a person of integrity --
    learned, intelligent.
Practicing so
as to know the goal,
when you've experienced the Dhamma,

    you get bliss.