口蜜腹剑
李林甫，唐玄宗时官居“兵部尚书”兼“中书令”这是宰相的职位。
此人若论才艺倒也不错，能书善画。但若论品德，那是坏透了，所以并不受欢迎。
李林甫常常贿赂宦官来告诉他皇上的喜好，然后再准备东西讨好皇上。因此皇上很倚重李林甫。
有一次，大臣李适之冒犯了李林甫，李林甫表面上并不在意，还装作对这个大臣特别好。
然后有一天，李林甫告诉李适之在华山后面藏着金子，并怂恿他让皇上去挖金。
玄宗立刻把李林甫找来商议，李林甫却说：“这件事我早知道了，华山是帝王风水集中的地方，怎么可以随便开採？别人劝您开採，恐怕是不怀好意；我几次想把这件事告诉您，只是不敢开口。”
如今当我们形容一个人是两面派，表面对人温文尔雅，但暗地伤人的人时，我们就用“口蜜腹剑”这个成语。
Honey in the mouth and swords in the stomach/Judas kiss
Li Lin-fu was a prime minister of China during the T'ang dynasty (唐朝, 618—907AD).
He was good at both calligraphy and painting, but had a crafty and sinister personality which made him disliked by everyone.
Li Lin-fu would bribe the palace eunuchs and concubines to tell him what the emperor liked, and then would immediately go prepare that thing for the emperor. The emperor was therefore very fond of Li Lin-fu, and trusted him unduly.
One time, the minister Li Shr-jr offended Li Lin-fu. Li Lin-fu pretended not to care, and was in fact especially nice to the minister.
Then on a day, he told Li Shr-jr about some gold that was hidden over in Hua Mountain, and encouraged him to suggest mining this gold to the emperor.
Li Shr-jr being of an honest and upright disposition, believed that it was true, and immediately went and told the emperor.
But when the emperor began to discuss this with Li Lin-fu, Li Lin-fu acted very frightened and said,
"Hua Mountain in the place where all of Your Majesty's auspicious aurora are gathered. If we were to mine that area, it could be very dangerous for you. Who is it that wants to harm you?”
Today we can describe someone who is two-faced and always nice on the outside and yet is mean to people behind their backs as having "Honey in the Mouth and Swords in the Stomach."