In Numbers, God tells Moses to tell Aaron, the priest, to give God’s blessing.
Numbers 6:24-26 (ESV)
24 The Lord bless you and keep you;
25 the Lord make his face to shine upon you and be gracious to you;
26 the Lord lift up his countenance[a] upon you and give you peace.
This can be thought of as a progression (general to specific). It can be thought of as 24: God the Father; 25: God the Son; 26: God the Holy Spirit.
In 1 Peter 2:5 we are told that we are to be a holy priesthood.
This means, as believers, we are all to bless one another.
The Moody Bible Commentary says that, “To bless someone means to pronounce the favor of God upon the person.”
This falls in line with my 2017 Christmas Box: We are Blessed to be a Blessing. (It’s not exactly the same, but related.)
That is, We are blessed to be able to pronounce God’s blessing on others.