Pearl:God speed
Greetings
It's a very powerful thing to not say hi or hello or goodbye to a person that you talk to. This is because it's part of Gods Word.
So if for example someone calls you and you don't know the person, answer by your name and then end the call maybe with thanks instead of bye.
Same can be applied to anyone that talk to you that you don't know if they abide in the doctrine of Christ or that you know that they don't abide in the doctrine of Christ.
So don't say hello and don't say goodbye to these people will help you. Test it out yourself. Let God be true and every man a liar.
God speed means greetings. So don't give any greetings. Don't say hello or goodbye or anything at all like that.
Also don't let people into your house that abideth not in the doctrine of Christ (2 John 9-11).
Notice though that Jesus rebukes not saluting everyone in Mt5:47.
Scripture
(II John 1:9-11 [KJV])
[9] Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son.
[10] If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed:
[11] For he that biddeth him God speed is partaker of his evil deeds.
(Luke 10:4) "Carry neither purse, nor scrip, nor shoes: and salute no man by the way."
Matthew 5:47 KJV
[47] And if ye salute your brethren only, what do ye more than others ? do not even the publicans so?
2 Kings 4:29 (KJV) Then he said to Gehazi, Gird up thy loins, and take my staff in thine hand, and go thy way: if thou meet any man, salute him not; and if any salute thee, answer him not again: and lay my staff upon the face of the child.