The chief priests picked up the pieces of silver and said, “It is unlawful to put this into the treasury, since it is blood money.”
The chief priests judge the money unsuitable for the treasury because it is blood money.
The verse shows their concern for ritual propriety.
3When Judas, who had betrayed Him, saw that Jesus was condemned, he was filled with remorse and returned the thirty pieces of silver to the chief priests and elders. 4“I have sinned by betraying innocent blood,” he said. 5So Judas threw the silver into the temple and left. Then he went away and hanged himself. 6The chief priests picked up the pieces of silver and said, “It is unlawful to put this into the treasury, since it is blood money.” 7After conferring together, they used the money to buy the potter’s field as a burial place for foreigners. 8That is why it has been called the Field of Blood to this day. 9Then what was spoken through Jeremiah the prophet was fulfilled: 10and they gave them for the potter’s field,