Matthew 21:4
All this was done, that it might be fulfilled which was spoken by the prophet, saying,
Cross-references
Matthew 1:22 uses the same 'fulfill what was spoken by the prophet' formula to introduce OT prophecy fulfillment.
Matthew 26:56 declares that events happened to fulfill Scripture — same theme as the fulfillment citation here.
Matthew 2:15 uses the same 'fulfillment formula' pattern, showing Matthew's consistent method of citing OT prophecies.
Matthew 12:17 is another fulfillment citation, continuing the pattern of connecting Jesus to prophecy.
Zechariah 9:9 is the prophecy of the king riding a donkey that Matthew directly cites as fulfilled here.
John 12:15 quotes the same Zechariah prophecy, confirming the fulfillment from another Gospel.
Mark 11:7 describes the same event of Jesus riding the colt, providing a parallel narrative account.