Is interfaith considered another gospel then? Because the apostles have something to say on that.
If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed:
For he that biddeth him God speed is partaker of his evil deeds.
But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
As we said before, so say I now again,
If any man preach any other gospel unto you than that ye have received, let him be accursed.
Again, neither bid such a one God speed either
For he that biddeth him God speed is partaker of his evil deeds.
It does show you can be a partaker of anothers sins, for example here...
And I heard another voice from heaven, saying,
Come out of her, my people, that ye be not partakers of her sins, and that ye receive not of her plagues.
And no wonder, because just like at this time he says,
For I will at this time send all my plagues upon thine heart, and upon thy servants, and upon thy people; that thou mayest know that there is none like me in all the earth.
But John and Paul say the same thing concerning them which preach another gospel (Paul moreso in his own demonstration). Where John might say dont even bid such a person God speed (who brings another gospel), Paul agrees in that by going one step further adding, "let him be accursed" (repeating this twice so theres no mistake).
What might seem a little strong handed in Paul is following the same course as shown in John its just not altogether silent.
So Paul is neither bidding any God speed but not altogether silent in how to let such be considered (which in this case, according to Paul as one accursed).
And accursed (whether of thing or man)
Is a thing devoted to God without hope of being redeemed , or a man accursed, devoted to the direst of woes or destruction
