上梁不正下梁歪
shàng liáng bù zhèng xià liáng wāi

If the upper beam is not straight, the lower ones will go aslant.;
A crooked stick will have a crooked shadow.;

上梁 shàng liáng=beam
Refers to a superior or elder：指上级或长辈。

比喻在上的人行为不正，下面的人也跟着做坏事。
This is an analogy about human behavior in that those in subordinate positions will follow the example set by their superiors.

Fish begins to stink at the head.;
If a leader sets a bad example, it will be followed by his subordinates.; When those above behave unworthily, those below will do the same.