Beracha

 Sefer HaIkkarim (04:19) My opinion therefore is that the blessings are not declarations of the future at all. A blessing is a prayer plus the bestowal upon the recipient of the capacity to receive the divine influence. Celestial influences descend upon the recipients through a chain of intermediate agents and in varying degrees, provided, however, that the recipients are worthy, and occupy a certain definite relation and order, and are in addition prepared to receive the influence in question. And if the transmission is interrupted in any of the intermediate agents, or the relation or order is changed, or the recipient is not prepared, the influence or relation gets confused, and the divine influence does not rest upon the person if the order is changed. For this reason there must be in the recipient the proper preparation to enable him to receive the influence in question. But if the recipient is not himself prepared to receive the divine influence, he may be prepared by a prophet or a righteous or pious man, and thus the one who bestows the blessing becomes an intermediate agent in causing the influence in question to descend. This is the reason for the laying on of hands by those who gave the blessings upon those who received them. The purpose was to confer upon the recipient of the blessing the capacity or preparation to receive the influence or good in question. Thus the pious or righteous man who conferred the blessing was a sort of channel conducting the divine influence. 

Sefer HaIkkarim (04:19) The same purpose is intended in the priestly benediction. The priests blessed the people in order that they (the priests) might be the intermediate agents to cause the divine influence to rest upon the recipients of the blessing in accordance with each one’s preparation. The lifting of their hands at the time of the blessing was a sort of laying on of hands. The priests blessed all Israel, or the congregation, because the many collectively are more prepared to receive divine influence than an individual. For it is impossible that there should not be among them some one who has preparation for receiving some measure of divine influence through the mediation of the priests. Of similar nature are the blessings which the righteous or the pious confer upon their recipients. The purpose is that the divine influence may rest upon the recipient through their mediation.

Sefer HaIkkarim (04:19) The question may be asked, how can the righteous or the pious man be an instrument through which a blessing may come upon a person when the pious man himself is poor and dependent upon the bounty of others. The answer is given by the Rabbis, who say that the merits of the righteous avail others, but do not avail the righteous man himself. 

Sefer HaIkkarim (04:19) After the influence is transmitted to the recipient of the blessing through the instrumentality of the blesser and in accordance with the amount of preparation of the recipient, the blesser has no power to stop the influence and prevent it from descending upon the recipient. For it descends of its own accord, the blesser being merely an instrument for the blessing to reach the recipient. Therefore though the instrument be removed, the blessing does not depart. It is the same as if a person drew by means of an aqueduct the water of a spring to a garden in order to promote the growth of the plants. The author of the conduit might cease to exist, but the stream made by the channel would not cease to water the garden.