Shakespeare.

How often in thy journeyings hast thou made thee instant friends,
Found, to be loved a little while, and lost, to meet no more;
Friends of happy reminiscences, although so transient in their converse,
Liberal, cheerful, and sincere, a crowd of kindly traits.

Tupper.

* * * * *

Heaven forming each on other to depend,
A master, or a servant, or a friend,
Bids each on other for assistance call,
Till one man's weakness grows the strength of all.

Pope.

In friendship we find nothing false or insincere; everything is straightforward, and springs from the heart.

Cicero.

Keep well thine tongue and keep thy friend.

Chaucer.