There's something tender about closing a letter or parting ways with a blessing. It's really more than nice words. A blessing infuses the blessed with the holy or sacred. A blessing is a powerful event.
In Judaism, a priest will raise his hands to offer a blessing like this.
It's no accident that pop culture has incorporated the meaning of the gesture to signify peace, welcome, and hospitality.
In the Christian culture, blessings are often done by ordained ministers during worship services. It is a passing on of God's presence and favor. It's also used to offer prayers of thanksgiving before a meal to the God who provided the food.
Since Islam has no clerical caste, Muslims bless each other when they meet and when they depart. If someone is grateful to Allah for their received blessings, it can be a tool for success in the afterlife. If they are not grateful, it becomes a tool of afterlife damnation. (wiki)
In Hinduism, a blessing is given as a gift or offering to a deity or an important person, and is then returned in the form of approval. Often the offering (food, clothing, etc.) that is given is consumed (eaten, worn) by the giver after it has been infused with the holiness of the deity. (wiki)
Ever wonder why we say, "bless you" to someone who has just sneezed? Lore suggests it was believed that a sneeze was the expulsion of a demon or devil residing inside. The blessing was to prevent the demon from re-entering the body. (There are other explanations, but I like this one the most.) When I was little, my Gramps used to say, "gesundheit," (German for "health," and often also used as a response to a sneeze) whenever I would yawn. Of course, this sent me into a fit of giggles, which interrupted my yawn mid-yaw.
However you bless or receive blessing, appreciate its origin, the people who taught you, and the God that hears us when we speak it and receive it. God bless you.
Narrative Lectionary Text: Ephesians 6:23-24
Peace be to the whole community, and love with faith, from God the Father and the Lord Jesus Christ. Grace be with all who have an undying love for our Lord Jesus Christ.