Because prayer to angels and saints is so absent from and contradicted by the Biblical sources and the earliest extrabiblical ones, advocates of the practice resort to unverifiable appeals to passages like Revelation 5:8 and 8:4. Neither passage suggests prayer to angels or saints, just as the angels' carrying bowls of wrath elsewhere in Revelation doesn't lead us to conclude that the angels are the recipients of that wrath. And the earliest interpreters of those passages in Revelation refer to how the prayers are directed to God. There's no mention of praying to angels or saints. For some documentation of that fact, as well as a discussion of the Biblical evidence against the abuse of Revelation 5:8 and 8:4 to support prayer to angels and saints, see here.
I came across another example while reading Tom Schmidt's translation of Anonymous Greek Scholia On The Apocalypse. In a passage about Revelation 5:8 that seems to have come from Origen, we read:
"Somewhere it is said, 'Let my prayer be directed as incense before you [God].' [Psalm 141:2] Bowls full of these incenses are the guides of those who genuinely pray to Christ." (Francis Gumerlock, et al., translators, Cassiodorus, St, Gregory The Great, And Anonymous Greek Scholia: Writings On The Apocalypse [Washington, D.C.: The Catholic University of America Press, 2022], 131)
Psalm 141:2, which is about praying to God, is cited, followed by a reference to those who "pray to Christ". Origen makes similar comments, including the citation of Psalm 141:2, in section 8:17 of Against Celsus.
For a collection of resources on the evidence against prayer to saints and angels, see here.
