yes I realize you don't consider prayer worship, but you are speaking to spirits of Christians, much like Saul trying to contact Samuel, yes these folks are very much alive, as all who are in Christ will never die, but speaking to spirits of departed humans is a communication that is a form of necromancy, If you want to do it, thats fine but since the old testiment, God has always forbidden speaking with spirits of people who left the world of the living. whether they were evil, or whether they were good saints or prophets like Samuel..........but maybe you think that was old testiment law, and that today now God wants you to communicate with passed on spirits, who dwell with Him......not sure where you get that idea
I realize that the conversation so far has been mainly Catholic and Protestants, and I've been in Eastern Orthodox studies for a little under a year and was Chrismated in the Antiochian Orthodox (the same Church of Antioch like in the Bible) just a few weeks ago and of course Catholics and us Orthodox don't agree on everything... But, for an alternate ancient point of view, forgive if I speak in error of Orthodox views, it is why I mentioned that I am, as we all are, very early on our road of learning...
Firstly, in the OT, death still existed. In the deutrocanon there are references to intercessions, I believe in the Maccabees... although I may be wrong. Honestly I don't know how it would play in since in the OT death still existed... more experienced Orthodox could probably answer that.
Christ destroyed death by death, by dying on the cross, decending into Sheol/Hades, and freeing all who were trapped there. After this point death doesn't exist.
By trying to tie praying for the intercessions of Saints and Mary to necromancy is very close to attempting to deny that Christ destroyed death. It is not necromancy because they aren't dead! That's the point, Christ did what we could not do. Adam and Eve introduced the sickness of sin into the world, which the result of the sickness of sin is death. God became incarnate, taking on our human nature, and overcame death. When Christ died on the cross and descended into Sheol, Sheol could not contain God. We could not do this on our own, and death became a tool of evil and a main component of why people sin. How many people sin because they are afraid of passing from their current earthly lives? They need more of this or want more of that... me me me and more more more, need to gather this all up before I die, only one life to live, etc... What kind of evil would someone do if they think either I do this or I "die".
To attempt to try to relate praying for the intercessions and help of Saints/Mary to necromancy is to downplay one of the most important things that Christ did. Destroying death!
When I was attending a Lutheran church they prayed to God for those who were sick, or those who's names had been added to a Prayer Request. Why would someone need that at all? Of course it is a normal thing to do. Asking Saints for intercession is the same principle, except unlike your pastor praying they are in the position where they can pray with the strength of the Will of God without the temptations and the evils of the World to intercede upon their prayers.
I apologize for jumping in on the middle of the discussion... but it felt like this wasn't fully explained. Quite possibly I haven't fully explained it either. I came from a protestant background, raised protestant, then Lutheran after meeting my now wife, and still things didn't add up when you actually credence to what Christ said... it finally did in the ancient Orthodox faith and we both converted.