Saying is one thing and doing another.
言行不一。

Seeing is believing.
眼见为实。

Seek the truth from facts.
实事求是。

Set a thief to catch a thief.
以贼捉贼。

Send a wise man on an errand, andsay nothing to him.
智者当差，不用交代。
(errand 跑腿：为完成某一项特殊任务，通常是为他人而走的一段路; / 差事：这种短途旅行的目的或意图)

Short accounts make long friends.
好朋友勤算账。

Put your shoulder to the wheel.
鼎力相助。

Soon learn, soon forgotten.
学得快，忘得快。

Soon ripe, soon rotten.
熟得快，烂得快。

Speech is silver, silence is gold.
能言是银，沉默是金。

Still water run deep.
静水常深。

Strike the iron while it is hot.
趁热打铁。

Strike the iron while it is hot.
趁热打铁。