“Thirty pieces of silver” refers to payment received for an act of treachery.
—“Betrayed with a kiss” refers to a supposed friend’s treachery.
Example: Patrick Henry warned his listeners about the supposed friendliness of the British. He warned, “Suffer not yourselves to be betrayed with a kiss.”
Example: When the senator abruptly changed his vote to support the wealthy developer’s project, some of his colleagues muttered that he would probably receive his thirty pieces of silver from the developer.