Matthew 27:6

‘And the chief priests took the pieces of silver, and said, “It is not lawful to put them into the treasury, since it is the price of blood.” '

The Chief Priests, who had paid the price of blood out of the Temple treasury, now became awfully pious. It was one thing betraying and destroying an innocent man, but they felt that it would be a gross sin to break the Temple rules. Thus they had the pieces of silver gathered up, piously indicated that as blood money it could not go into the Treasury (the place of dedicated money - ‘korbanas' - from which it had come), and set it apart for the good of Gentiles who were after all already unclean. It would not do for the Temple or the Jewish race to be tainted by blood money (initially paid out by their representatives for this purpose). It is all so typical of the hypocrisy of men and women through the ages, especially those in authority, that the truth of the matter cannot be doubted, and the matter of fact way in which the story is told confirms its accuracy. No lesson is drawn from what happened.