The contrary of blessing is cursing. A curse is a sentence and a seal of mischief. It is, like blessing, a judgment imprinted upon the forehead and the heart. It shuts off the sources of life. God has imparted a portion of his power to bless and to curse to those whose vocation it is to create life.
Priests possess it.
As parents engender natural life, so the priest begets the supernatural life of grace. To give life is the nature and office of both. And he also may attain to the power of blessing who no longer seeks himself but in perfect simplicity of heart wills to be the servant of him Who has life in himself. But the power to bless is always and only from God. It fails wholly if we assume it of ourselves.