Strange, because the totality of scriptures seem to me to be loaded with them. The first reference to a blessing of bread and wine comes in Genesis 14:18

Fine you might say it's bread and wine. That doesn't support Transubstantiation on its own, but it helps build the house. We see in Hebrews 7 that Melchizedek is a type of Christ. He offered bread and wine to Abram, which is the same thing Christ offers to the Twelve that night in the Upper Room.
While they were held as slaves in Egypt the Israelites found someone who would lead them to freedom, Moses. God told the Israelites to celebrate a special feast, Passover. He would go through the land slaughtering the firstborn sons of Egypt, but the Jewish people would be spared because of blood from a freshly slaughtered Lamb on their doors.
The Passover feast had some special rules. Each family was to take a spotless firstborn male lamb from their flock, slaughter it and roast it. They were also told that the entire lamb had to be consumed, nothing could be left overnight. They were also to throw out all the leaven and eat only unleavened bread.
Interestingly enough especially later on anyone desiring to take part in the Passover feast had to be a Jew. It was a closed feast, that will come back up later.
I mentioned previously that Hiram Diaz refused to answer my question regarding whether the lamb was to be eaten. I think he knew where I would take him if he answered me. Revelation that great and terrible book that closes scripture. In between all of the frightful bits of prophesy Revelation is actually a great Passover liturgy.
Interestingly in chapter 5 we see Christ referred to as the lion of Judah and the root of David. However when St. John looks he sees a lamb appearing as though it has been slain Rev. 5:5-8


That being said, if even in his heavenly glory Christ is the newly slain lamb of the Passover. He must even during the Incarnation have still existed outside of time as humans know it, thus for Him the Law has always been fulfilled. Thus rendering any attempt to turn Transubstantiation into some sort of sin against the Law moot.
Let's go back to that Upper Room, Christ having "eagerly desired" to celebrate one last Passover with His apostles reclines at table with the Twelve Lk. 22:12




Curiously the institution narrative is absent in John's Gospel. However in John 6 we see the famous Bread of Life discourse in which Christ explains that for His disciples to have eternal life they must eat His flesh and drink His blood.
Some of you out there might now be saying sure but none of this says that a priest can say some words over a wafer of bread and a cup of wine and make it truly the Body of Christ or the Blood of Christ. Indeed that is never directly taught. However it is clear that Christ intends for the Apostles to be the beginning of a new ministerial priesthood. As such He implores them to repeat the blessing over the bread and wine "Do this in memory of Me."
The New Testament ministerial priesthood is perfectly foretold in the Old Testament as Malachi 1:11

Pretty sure you will find a Catholic Mass being offered somewhere in the world every hour of every day of every year. Save for Good Friday, no Mass that day, no sacraments at all in fact, except in cases of dire need.
So Communion for a Catholic is all about receiving the Lord whole and entire: Body, Blood, Soul and Divinity with every reception of the sacrament. It is a closed feast like the OT Passover after all we have to protect the solemnity and dignity of such a great mystery.

For me the faith stands or falls on this one thing, that is why I go to such lengths to defend it. It's also why I get so angry about people who are so derisive about it, especially without a sound attempt at a refutation.