Zechariah 11:12-13 I told them, "If you think it best, give me my pay; but if not, keep it." So they paid me thirty pieces of silver. And the Lord said to me, "Throw it to the potter" - the handsome price at which they priced me! So I took the thirty pieces of silver and threw them into the house of the Lord to the potter.

Matthew 27:9 Then what was spoken by Jeremiah the prophet was fulfilled: They took the thirty silver coins, the price set on him by the people of Israel.

Though the majority of the quotation is from Zechariah 11:12-13, the content is also related to Jeremiah 19:1-13. The context of Jeremiah reveals it concerns the judgment for the shedding of innocent blood (Jer. 19:4). In addition, Jeremiah speaks of a potter (Jer. 19:1, 11). Moreover, Matthew's "Field of Blood" recalls Jeremiah's designation of Topheth as the "Valley of Slaughter" (Jer. 19:6), which also was to become a burial ground (Jer. 19:11).

From the Word Biblical Commentary, Hagner states:

If we attempt to reconstruct how Matthew came to this fulfillment quotation, we may conclude the following. Matthew had from Mark that Judas was paid "money" (Mark 14:10). Matthew may have had a separate tradition about the amount of "thirty," but perhaps it is more likely that he imports this detail from the Zechariah quotation in anticipation of using it later in connection with the potter's field (cf. its presence already in Matt. 26:15). Because Zechariah 9-14 was particularly important for the early church as a resource of prophecies fulfilled by Jesus (cf. in Matthew; Zech 9:9 in 21:5; Zech 13:7 in 26:31) and in particular because Zechariah 11 speaks of a shepherd "doomed to slaughter," taken obviously by Matthew to refer to Jesus (Matt. 26:31), Matthew finds the correspondence between Zechariah 11:13 and the story of Judas taking silver coins for betraying Jesus a compelling one. Matthew also probably had an element from historical tradition about a "field of blood" associated with Judas reward money (cf. Acts 1:18), which he may also have known as the potters field. Thus Matthew finds a further correspondence in the twofold statement of Zechariah 11:13 that the pieces of silver were thrown "to the potter" - why else, according to Matthew, than to buy the field in question (Zech 11:7)? The combination of these motifs may thus be responsible for the association with Jeremiah.

Reference:

Richard Pratt, General Editor. Spirit of the Reformation Study Bible, Zondervan, Grand Rapids, MI, 2003.

Hagner, D. A. Word Biblical Commentary, Vol. 33B: Matthew 14-28. Dallas: Word, Incorporated, 2002.