# hit your two hands together

"clap your hands to show that you are very sad"

# even a third time

"again and again"

# A sword for the ones to be slaughtered

"It is a sword for slaughtering people"

# It is a sword for the many to be slaughtered

"It is a sword for slaughtering many people"

# piercing them everywhere

"attacking them from every side." Some Bibles translate this as "which enters into their rooms." This means no matter where they hide, the sword will kill them.

# piercing them

This refers to the people of Jerusalem and of the land of Israel.