อมพระมาพูด

From อม (om, “to hold in the mouth”) +‎ พระ (prá, “god, deity, priest, etc; representation thereof, as image, statue, etc”) +‎ มา (maa, “used to indicate motion towards the speaker's direction”) +‎ พูด (pûut, “to speak; to utter”); meaning "to speak with a [holy] image in the mouth/on the tongue".

อมพระมาพูด • (om-prá-maa-pûut)

1. (idiomatic, chiefly used to express negation) to support one's own speech by alluding to a sacred thing.
   • ต่อให้อมพระมาพูดก็ไม่เชื่อ

     dtɔ̀ɔ hâi om-prá-maa-pûut gɔ̂ mâi chʉ̂ʉa

     Even [you] speak with a sacred image in your mouth, [I] won't believe [you].