# so that it might take hold ... shake the wicked out of it?

"You have never given ... so that it might take hold ... shaken the wicked out of it.". This is the end of the question that begins with the words "Have you given" in verse 12 and it expects a negative answer.  

# take hold of the edges of the earth

"grasp the ends of the earth"

# shake the wicked out of it

"shake wicked people out of the earth". The daylight is pictured as causing wicked people to leave like shaking something to remove unwanted things.