Matthew 26:15

‘And said, “What are you willing to give me, and I will deliver him to you?”

Approaching the chief priests he put to them his proposition. For the right sum he would enable them to arrest Jesus somewhere where it was quiet. The question was as to how much it was worth to them. It may well be that he himself named the sum that he required on the basis of the Old Testament indication of the value of a prophet, and of a moribund Shepherd of the people. See Zechariah 11:12. He had it all carefully thought out. Alternately the chief priests may have made the offer for similar reasons. But whichever way it was, the price was agreed. Little did he realise that his name, and the price he would receive, would become as famous as the act of the woman who had anointed Jesus, but that in his case he would become proverbial for treachery, dirty dealings and betrayal. Ironically he too would be remembered wherever the Gospel was proclaimed.

‘And they weighed to him thirty pieces of silver. '

The chief priests were so eager to get their victim that they seemingly paid the money out up front, and this to someone who had criticised the woman earlier for not thinking of the poor. (Ironically it would later actually be used for the poor - Matthew 27:7). Note the emphasis on the deliberate ‘weighing of the silver'. It was a deliberate payment of blood money, a price sarcastically described by Zechariah as ‘the goodly price that I was valued at by them' (Zechariah 11:13). It was the price of a moderately valuable slave. (In LXX the verb used here regularly translates the Hebrew verb for ‘weighed out'. It means literally, ‘placed, stood'). Matthew appears to be suggesting that he was paid it there and then, although he does not actually say so. Certainly Judas received it early enough to be able to fling it back at the chief priests later (Matthew 27:3).