Sirach 5:12

12 If you have understanding, answer your neighbor, but if you don't, clap your hand over your mouth.

Sirach 5:12 In-Context

10 Be firmly grounded in your understanding, and let your speech be consistent.

11 Listen carefully, and utter a patient reply.

12 If you have understanding, answer your neighbor, but if you don't, clap your hand over your mouth.

13 Speaking brings glory or dishonor. Indeed, the tongue can be a person's downfall.

14 Don't get a reputation for being a slanderer, and don't set traps for people with your speech, because shame comes to the thief, and terrible blame comes upon the deceitful.