At the end of my shift tonight I was thinking how Satan masquerades as an angel of light and the question came to me that if Satan masquerades as an angel of light, how did people from the bible know that when they were speaking with an angel that he was sent by God? I know that the way people would discern a true prophet is if what he said came to pass and if it did not, that prophet was not sent by God.
I had a similar question: in the transfiguration, how did the Apostles know it was Moses and Elijah that appeared to Jesus?
It seems that Wheat (as opposed to Tares) have an inbuilt discernment of spirit capability.
Now I heard or read something interesting. I do not know why, but it seems that there is a protocol set by God in the spiritual realm.
In some pentecostal / charismatic circles, they affirm that entities are bound to identify their allegiance.
So in theory whenever confronting any "other worldly" being, one must ask: Who do you serve?
According to some believers, envoys from God immediately respond: Jesus Christ.
Others beat about the bush.
Example: a pentecostal sister was driving and something that may be construed as an alien craft kind of trailed her, and she started to get some sort of communication in the mind from them.
She stopped the car and mentally asked them "who do you serve?", the answer came in hesitant tone: we have choices, different alternatives, etc.
She basically told them to leave her alone if they did not serve Jesus Christ (mentally), and surprisingly, they left.
Then there is the story that Ireneaus saw an apparition of what seemed to be Jesus and asked him to bow. He refused because the apparition had a crown, and Ireneaus remembered that Jesus was not crowned until the end. So Ireneaus told the apparition to depart, and it did.
Interesting topic but maybe more research is needed.