A friend is never known till a man has need 需要之时方知友。
No man is the whole of himself; his friends are the rest of him 任何人自己都不是完整的;他的朋友是他的其余部分。
A life without a friend is a life without a sun 人生在世无朋友，犹如生活无太阳。
Be slow in choosing a friend; slower in changing 选择朋友要审慎，摒弃更要审又慎。
A friend in need is a friend indeed 患难见真交。
Betraying a trust is a very quick and painful way to terminate a friendship.---Ralph Waldo Emerson, American thinker 背信弃义会迅速而痛苦地断送友谊。---美国思想家 爱默生
Both together do best of all. 二人同心，无往不胜。
Do not speak of your happiness to one less fortunate than yourself. 不要向不如你幸福的人说你自己的幸福。 ——Plutarch
Don’t ask others to also do not allow others to do the dirty things, as a principle of friendship既不请求别人也不答应别人去做卑鄙的事情，为友谊的一项原则。 --（古罗马）西塞罗
Short reckonings make long friends.好借好还再借不难。怎么外国人的朋友的名言都是借来借去...
With friends like that, who needs enemies?说的是如果有这种人做朋友，还用得着敌人吗?说这朋友很不够义气。
A friend is easier lost than found.得朋友难，失朋友易。