Who are the modalists?
The ancient modalists were condemned heretics such as Noetus, Sabellius, and Praxeas. We don't have much record of their own writings, and what we do know of them is based on what men like Tertullian and Hippolytus wrote in response to them. So we know very little of their actual theology.
In modern times, Oneness Pentecostalism has ...
Intercession is not the same as mediation!
As other answers have said perfectly adequately, there is plenty of biblical support for interceding for one another and the example of the Apostle Paul requesting this intercession from other (living!) saints; although there is no particular scriptural warrant to explicitly endorse asking for such intercession ...
There are a variety of things going on here. (FWIW, I'm an Anglican who holds to the Catholic faith, so I'm not explaining my own beliefs here. I'll try as best I can to give a fair account of others' beliefs.)
Many Protestants believe that prayer should only be directed at God and that prayer to anything else is ipso facto idolatry. To pray to ...
I think the short answer is that there is Biblical precedent for this sort of intercessory prayer.
Here are a few examples:
2 Corinthians 1:11 (ESV)
You also must help us by prayer, so that many will give thanks on our behalf for the
blessing granted us through the prayers of many.
Philippians 1:19 (ESV)
for I know that
through your prayers ...
Mediation is a relative term. That is you can't mediate something from yourself to someone else per se. For example, Christ mediates between God and man (being Himself both).
Thus, any of us can mediate (go between or relay something/be the instrument of confering something to someone else):
1 Timothy 2:2
First of all, then, I urge that petitions, ...
In addition to lonesomeday's excellent answer I would also like to cite the following Scriptures where both Paul and James indicated that others should offer intercessory prayer for either them or others.
All Scripture is quoted from the King James translation.
In the following instance we see Paul asking for their prayers, to aid him in his work for the ...
The apostle Paul prays for the living and prays for other Christians. So it seems perfectly natural for Christians to ask for prayer from other living Christians.
Eph 1:16 Cease not to give thanks for you, making mention of you in my
James 5:16 - ... pray one for another ...
Among many others which others have pointed out.
I think the ...