二人同心，其利断金；同心之言，其臭如兰
er ren tongxin, qi li duan jin; tongxin zhiyan, qi xiu ru lan
Tongxin means “the same mind”; jin refers to gold or metals; xiu means smell; lan are orchids. This proverb, taken literally, means that when two people are of the same mind, their keenness cuts through metals; the words of those who are of one mind are as fragrant as the orchids.

This proverb originates from the I Ching. A variant of this saying is a phrase “the friendship of jin-lan,” which usually describes a strong friendship or brotherly relationship between two  people.

镜破不改光，兰死不改香
jing po bugai guang, lan si bugai xiang
Jing refers to mirrors; bugai means “does not change”; guang means “light”; xiang refers to fragrance. This proverb, taken literally, means that broken mirrors never change their nature of mirroring images; a withered orchid still smells fragrant. 

This proverb originates from a poem by Meng Jiao (751-814) in the Tang Dynasty (618-907). It is used as a metaphor to praise those who suffered a difficult time in life but still uphold moral principles.

兰室鲍肆
lan shi bao si
Lan refers to orchids; shi is room; bao means salted fish; si are shops. This idiom, taken literally, means a house full of orchids and a shop selling salted fish. A house full of orchids is a metaphor for a good environment while a salted fish store is a symbol of bad influence.

According to the Book of Rites by Dai De, Zeng Shen, a famous student of Confucius once said: “Associating with a virtuous man is like walking into a room full of orchids. As time goes by, one would not smell the fragrance for he has emerged in it. Associating with unvirtuous man is like walking into a store selling salted fish. As time goes, one also would not feel the stinky smell for he has emerged in it. Therefore one should be prudent about choosing friends he is to leave or associate with.”

This idiom is used to warn of the opposing influence the outside environment might have on a person and that a person tends to be influenced by the company he keeps.