...if you consider any man a friend whom you do not trust as you trust yourself, you are mightily mistaken and you do not sufficiently understand what true friendship means.
1923, William Armistead Falconer translating Cicero as De Amicitia, Loeb Classical Library, Vol. XX, p. 34:
...he who looks upon a true friend, looks, as it were, upon a sort of image of himself. Wherefore friends, though absent, are at hand; though in need, yet abound; though weak, are strong; and—harder saying still—though dead, are yet alive; so great is the esteem on the part of their friends, the tender recollection and the deep longing that still attends them.
...you are my devoted friend too. You do more and work harder and oh shit I'd get maudlin about how damned swell you are. My god I'd like to see you... You're a hell of a good guy.
1933 Dec. 12, Walter Winchell, "On Broadway", Scranton Republican, p. 5:
Definition of a friend: One who walks in—when the rest of the world walks out.
John and I have been friends ever since we were roommates at college. Trust is important between friends. I used to find it hard to make friends when I was shy.
The dirty secret of the internet is that all this distraction and interruption is immensely profitable. Web companies like to boast about […], or offering services that let you "stay up to date with what your friends are doing",[…]and so on. But the real way to build a successful online business is to be better than your rivals at undermining people's control of their own attention.
1813, Samuel Foote, The Commissary, Etc., page 17:
Time has been, when a gentleman wanted a friend, I could supply him with choice in an hour; but the market is spoiled, and a body might as soon produce a hare or a partridge […]
Meanwhile on The View, Whoopi Goldberg and friends continue to issue forced apologies for their assumptive comments regarding non-profit organisation Turning Point USA...
friends is found as an invariable plural in the phrases make friends with and be friends with: I am friends with her; He made friends with his co-worker.
In older texts and certain dialects, the prepositional phrase to friend means "as a friend or an ally", for exampleː "with God to frend (Spenser)". The antonym to the phrase to friend is to fiend.