rend the air(shake heaven and earth)

as hard as the nether millstone

cause alienation by spreading rumours

feign ignorance

Heaven principles are clear and transparent.

The sky is high and the air fresh.

a murky sky over a dark earth

be bound by a common hatred for the enemy

The way of Heaven is not partial.

make empty promises(blow bubbles)

stir up enmity(tell tales out of school)

run into bumps and bruises

Evildoers are always banded together.

Iron and copper casting

honeyed words(an oily tongue)

pass on information to

Iron walls and brass partitions

to name in the same day

Find spiritual sustenance in sth.

give lip service to