# I was like a gentle lamb being led to the slaughter

This speaks of Jeremiah being unaware of his enemies' plans to kill him by comparing him to a lamb who is being led to be slaughtered.

# being led to the slaughter

"that my enemies were leading to a butcher" 

# Let us destroy the tree with its fruit

Jeremiah's enemies speak of killing him as if he were a fruit tree that they were planning to destroy.

# Let us cut him off from the land of the living

"Let us kill him so he is no longer in the land of those who are alive"

# his name will be no longer remembered

"people will no longer remember his name"