The mainstream view during the Biblical era and among the earliest extrabiblical sources was that we should pray only to God, not to saints and angels. See my collection of articles arguing for that conclusion, along with discussions of ongoing opposition to praying to saints and angels in later generations of pre-Reformation church history, here.
Origen is an important extrabiblical source on the topic. He's significant for more than one reason. He wrote a lot of material that's extant. He wrote an entire treatise on prayer. He addressed prayer many times in other contexts. The subject of who we should pray to came up a lot in his response to Celsus, a second-century pagan who consulted one or more Jewish sources when studying Christianity. So, Origen's treatise against Celsus reflects how a variety of sources perceived Christian views of prayer at the time.
I've written too many posts about Origen's material on prayer for me to link all of them here. You can use something like a Google search to find the relevant posts or see our collections of posts under post labels like Origen and Prayer. The post here goes into a lot of depth in response to some common arguments about Origen put forward by advocates of praying to saints and angels. And here's one about some material in Origen's Homilies On Ezekiel that's sometimes misused to make it appear that Origen supported prayer to angels. There are many other relevant posts in our archives, including some in comments sections of threads and in posts that don't have the Origen label, for example. If you're interested in an issue related to Origen and praying to saints and angels, there's a good chance you can find some relevant material somewhere in our archives.
It's important to go into discussions of this topic with some distinctions in mind. Supporters of praying to saints and angels will often change the subject, as if support for other prayer practices implies support for praying to saints and angels when it actually doesn't. They'll bring up passages in Origen about whether angels pray with us, even though that's a distinct issue from whether we should pray to angels. Or whether saints in heaven pray for us will be cited, as if it implies support for praying to those saints, which it doesn't. You have to be careful to consistently maintain such distinctions. Otherwise, your thinking about these issues and the discussions you have about them will go off track.
