This explanation talks about 2 John 1:10. We as Christians should reject false preachers from our gatherings, not to endorse them as people who are worthy of our faith.
I would not have faith in humans and in false GOD cause they would bring to doom. Eternity must be perfect and so all of I am, and my faith should be all about Jesus.
When we greet a person in the name of God, would it mean or would it imply that that person has been saved?
Shalom for you! really, a person who blatantly rejects Jesus would have Godly eternal perfect peace?
Judge for yourself...
However during times of trouble, would they receive us in their house as Christians?
So according to the parables of the good Samaritans, if they would receive us we too should consider them as our brothers. And surely God will repay them for being our family in those times.
So what's my position on this issue? I believe that people who would help the Christians will receive peace from God, if they are helpers of Christians blessings will come to them. But if they rejected Christ, then the blessings will not be for them forever.
"And if the son of peace be there, your peace shall rest upon it: if not, it shall turn to you again" Luke 10:6 from (http://www.blueletterbible.org, Jan 2013)