If you are talking about Evangelical Protestants (Baptist, Free, Covenant, etc.), USE THE BIBLE!!! Do not use anything else. They won’t be impressed by personal testimony, the saints (especially the saints), or any books written by humans.
And use a Protestant Bible. The New International Version (which I hate, BTW), is generally the Bible of choice with Evangelical Protestants.
There are several apologists who have used the Bible to explain the Eucharist. One apologist that doesn’t get mentioned often on CAF is Edward Sri. He has some absolutely amazing Bible studies that start with Genesis and take us through the Bible demonstrating God’s plan for salvation that culminated in Jesus establishing Holy Communion at His Last Supper.
It was after attending this Bible study that my Evangelical Protestant (Assemblies of God) father-in-law told us that he would love to become a Catholic (he still hasn’t made the step, but he has suffered from some serious physical setbacks, and his wife has Alzheimers, so it’s hard for him to “take action” on anything!).
Even if you don’t have time to do a study of some of Edward Sri’s writings, at least illustrate Eucharist by going back to the Old Testament and the establishment of the Passover, and relate this to the dissolution of Passover by Jesus, Who replaced Passover with Holy Communion, in which we still “eat real food.”
Also, make use of John Chapter 6, which is really hard for Evangelical Protestants to explain away (although they will tell you that Jesus didn’t really mean “eat,” but was speaking symbolically.)
Finally, think about something my daughter says. In the Gospels, Jesus often uses everyday objects to help people understand Who He is. E.g., “I am the Door,” or “I am the Vine.”
BUT…only once does He say, “This Bread is My Body.”
Not “I am this Bread” (an analogy), but “This Bread is Me”–a statement of fact.
Hope this is helpful. Use that Bible! If you don’t, they won’t take you seriously.
