# You know this

Possible meanings are 1) "Know this" is a command to pay attention to what I am about to write or 2) "You know this" is a statement saying that I am about to remind you of something that you already know.

# Let every man be quick to hear, slow to speak

These sayings mean people should first listen intently, and then consider carefully what they say. 

# slow to anger

"not get angry quickly"