Proverbs 27:14
NKJV - 14 He who blesses his friend with a loud voice, rising early in the morning, It will be counted a curse to him.
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I looked at my NASB and Proverbs 27:14 has a footnote leading to Psalm 12:2 leading to Jeremiah 9:8.
What I think is that the custom of the people is to bless each other, saying "peace" when they meet in the morning, but later during the day they plan an ambush for their neighbor; therefore the blessing of "peace" is just a lie and a deception. Because they lie blessing with their lips but plan evil in their heart instead, they are accursed as liars. If you read the gospel of Matthew when the 70 are sent out they had to give their blessing of peace upon entering the house. So it is common practice to say "peace" as a greeting. This is what I understand from it..