Q: How does the blessing of a tzaddik work? How is it different from the blessing of the Kohen (Priest)?
A: The ‘mechanism’ through which a blessing passes, whether it is the blessing of a tzaddik or the blessing of a Kohen, is love. Unlike the Kohen, the tzaddik is not limited to specific verses in his blessing. But both “bless His Nation of Israel with love.”
Current physics speaks of different forces that rule nature. Every force is transferred by particles (such as electromagnetism, which is transferred by means of photons). If a tzaddik or Kohen has love-force in his heart, he can transfer it by means of the ‘love particle,’ thereby radiating it to the recipient of his blessing and to the entire world.