A prayer of blessing is a prayer that calls down God’s blessing upon us. From God alone all blessings flow. His goodness, his closeness, his mercy—that is blessing. “May the Lord bless you” is the shortest prayer of blessing.
Every Christian should call down God’s blessing upon himself and upon other people. Parents can trace the Sign of the Cross on their child’s forehead. People who love each other can bless one another. Furthermore a →PRIEST, by virtue of his office, blesses explicitly in the name of Jesus and on behalf of the Church. His request for blessings is made especially effective through Holy Orders and the prayer power of the whole Church.
(*) YOUCAT, Youth Catechism of the Catholic Church, 2013