Does anybody know of the counterarguments that are raised when Catholics rely on Revelation 5:8 to make the case for prayer to saints? I mean counterarguments that specifically address the Catholic understanding of Revelation 5:8, not generic counterarguments opposing prayer to saints like prayer = worship, etc.
The easiest one would be the fact that the term translated ‘saints’ is 'αγιοι, which is ‘holy people’. As such, it is used
throughout the New Testament to refer to living believers, rather than a separate class of the dead and elevated. Thus, were I, not being Catholic, disputing your reading of the passage, I would simply point out that there is no intra-textual reason to read it as being different from the common usage: i.e., the prayers of the saints are the prayers of
all of the believers, and not just of ‘saints’ in the most common sense within Catholicism, i.e., patron saints.
And, if so, how to address those counterarguments?
I would advise against directly contradicting it: from a literary perspective, it is the better reading, and it contains something which most Protestants do not consider.
If you want to talk (not argue) with Protestants about the idea of saints, have them read such passages as
Luke 16:19-31 and
Hebrews 12:1, and ask them whether these passages indicate that the dead are conscious. They could argue that other passages refer to the dead ‘falling asleep’, which is quite true; since they are the ones who (most likely) believe in the literality of the text, you can ask them to reconcile the difference, which they will endeavour to do without contradicting Luke or Hebrews. They might claim that the passage in Luke is merely a parable, but, if it is a parable not based in reality, it is one which has certainly misled a vast number of believers over history, and was, therefore, a very irresponsible thing to have included in the first place. When they affirm that those passages do indicate that the dead are conscious, ask them why a conscious Christian who has gone to be with God would choose
not to intercede for those who are left behind.
From there, they are likely to object to the Catholic classification of only
some people as being saints. What you can point out there is that, according to the
Catechism, all of God’s people
are saints, the difference between the Catholic-Orthodox view and the Protestant one being that Protestants tend to forget the believers who are dead. From there, you can discuss the idea of
patron saints, and how they are singled out as being people of whose salvation the Church is sure because of the virtue of their lives. Thus, the view of such saints is
inclusive, not exclusive: the Church is saying, “We are sure that these people are saved. About other individuals, we do not know, and so we will not claim to know.”