A blessing is the bestowment of divine favour and protection. It is a great privilege and an honour. It does, however, come with great responsibility. In that sense, it is a double-edged sword: it cuts both ways. For every blessing that you receive, G-d expects you to do something with it, make something of it, disseminate the fruits of it.

The Aaronic Blessing

Shefa Tal: During the course of the blessing, the hands of the Kohanim are spread out over the congregation, with the fingers of both hands separated so as to make five spaces between them. The Kohen raises his hands, with the palms facing downward and the thumbs of his outspread hands touching. The four fingers on each hand are customarily split into two sets of two fingers each (thus forming the letter Shin (שׁ), an emblem for Shaddai, “Almighty [G-d]”) [Text and image: Wikipedia]