I found this in a book written in 1604, Characters of Vertues and Vices by Joseph Hall, Bishop of Exeter.
I suspect most of you would see yourselves described here, if you were not so good at overlooking your own best qualities:
Of the true friend.
His affections are both united and divided; united, to him he loveth; divided,
betwixt another and himself: and his own heart is so parted, that while he
hath some, his friend hath all. His choice is led by virtue, or by the best of
virtues, religion; not by gain, not by pleasure; yet not without respect of
equal condition, of disposition not unlike; which, once made, admits of no
change; except he whom he loveth, be changed quite from himself; nor that
suddenly, but after long expectation. Extremity doth but fasten him, while
he, like a well wrought vault, lies the stronger by how much more weight he
bears. When necessity calls him to it, he can be a servant to his equal, with
the same will wherewith he can command his inferior; and though he rise to
honour, forgets not his familiarity, nor suffers inequality of estate to work
strangeness of countenance: on the other side, he lifts up his friend to
advancement with a willing hand, without envy, without dissimulation.
When his mate is dead, he accounts himself but half alive; then his love, not
dissolved by death, derives itself to those orphans which never knew the
price of their father; they become the heirs of his affection and the burden of
his cares. He embraces a free community of all things, save those which
either honesty reserves proper, or nature; and hates to enjoy that which
would do his friend more good. His charity serves to cloak noted infirmities,
not by untruth, not by flattery, but by discreet secrecy, neither is he more
favourable in concealment than round in his private reprehensions; and
when another's simple fidelity shows itself in his reproof, he loves his
monitor so much the more by how much more he smarteth. His bosom is his
friend's closet, where he may safely lay up his complaints, his doubts, his
cares; and look, how he leaves so he finds them, save for some addition of
seasonable counsel for redress. If some unhappy suggestion shall either
disjoint his affection or break it, it soon knits again, and grows the stronger
by that stress. He is so sensible of another's injuries, that when his friend is
stricken he cries out, and equally smarteth untouched, as one affected, not
with sympathy, but with a real feeling of pain; and in what mischief may be
prevented he interposeth his aid, and offers to redeem his friend with
himself; no hour can be unseasonable, no business difficult, nor pain
grievous, in condition of his ease; and what either he doth or suffereth, he
neither cares nor desires to have known, lest he should seem to look for
thanks. If he can therefore steal the performance of a good office unseen, the
conscience of his faithfulness herein is so much sweeter as it is more secret.
In favours done, his memory is frail; in benefits received, eternal: he
scorneth either to regard recompense, or not to offer it. He is the comfort of
miseries, the guide of difficulties, the joy of life, the treasure of earth, and
no other than a good angel clothed in flesh.