Question:

Answer:

Your question about the mention of "Jeremiah" in Matthew 27 is a very difficult one:

Then was fulfilled what had been spoken by the prophet Jeremiah, saying, "And they took the thirty pieces of silver, the price of him on whom a price had been set by some of the sons of Israel, and they gave them for the potter's field, as the Lord directed me," (Matt. 28:9-10, English Standard Version)

Commentators usually either skip it or come up with theories that are unacceptable, as I have discovered in consulting many scholarly works.

One possible approach is to read Matthew as a free and complicated adaptation of Zechariah 11:

Then I said to them, "If it seems good to you, give me my wages; but if not, keep them." And they weighed out as my wages thirty pieces of silver. Then the LORD said to me, "Throw it to the potter"--the lordly price at which I was priced by them. So I took the thirty pieces of silver and threw them into the house of the LORD, to the potter. (Zech. 11:12-13, ESV)

along with a composite reference to Jeremiah 18:

The word that came to Jeremiah from the LORD: "Arise, and go down to the potter's house, and there I will let you hear my words," (Jer. 18:1-2, ESV)

and possibly Jeremiah 32:

Jeremiah said, "The word of the LORD came to me: Behold, Hanamel the son of Shallum your uncle will come to you and say, 'Buy my field that is at Anathoth, for the right of redemption by purchase is yours.' Then Hanamel my cousin came to me in the court of the guard, in accordance with the word of the LORD, and said to me, 'Buy my field that is at Anathoth in the land of Benjamin, for the right of possession and redemption is yours; buy it for yourself.' Then I knew that this was the word of the LORD. And I bought the field at Anathoth from Hanamel my cousin, and weighed out the money to him, seventeen shekels of silver. I signed the deed, sealed it, got witnesses, and weighed the money on scales. Then I took the sealed deed of purchase, containing the terms and conditions and the open copy. And I gave the deed of purchase to Baruch the son of Neriah son of Mahseiah, in the presence of Hanamel my cousin, in the presence of the witnesses who signed the deed of purchase, and in the presence of all the Judeans who were sitting in the court of the guard. I charged Baruch in their presence, saying, 'Thus says the LORD of hosts, the God of Israel: Take these deeds, both this sealed deed of purchase and this open deed, and put them in an earthenware vessel, that they may last for a long time. For thus says the LORD of hosts, the God of Israel: Houses and fields and vineyards shall again be bought in this land.'" (Jer. 32:6-15, ESV)

(Just how free Matthew's adaptation is can be seen by his use of the third person plural, "they gave them for the potter's field," whereas Zechariah uses the first person singular, "So I took the thirty pieces of silver and threw them into the house of the LORD, to the potter"). It's reasonably clear that Matthew had both Zechariah and Jeremiah in mind.

The important truth to keep in mind is that everything that befell Jesus was according to the plan and providence of God in fulfillment of prophecy. In his prophecy Zechariah mocks the price by which God's faithful shepherd was valued (Zech. 11:13, "Then the Lord said to me, 'Throw it to the potter'—the lordly price at which I was priced by them," ESV). Similarly, Jesus the Shepherd of Israel was valued at the paltry sum usually reserved for slaves. Judas, a son of Israel, had negotiated the price of Israel's Messiah, the One whose worth is priceless.

So what to do with the money? The now-scrupulous priests and elders of Israel must keep the blood money outside the sacred precincts of the temple!

I hope some of the thoughts I've put together will be helpful to you.