# For he will be thrown into a net by his own feet; he will walk into a pitfall

"It will be as though he led himself into a net, as if he walked right into a pitfall" or "His own feet will lead him into a net." 

# a net

People used nets to catch animals.

# a pitfall

a pit that has branches and leaves over it so that an animal will walk onto the branches and leaves and fall in