Did you notice all the hustle and bustle in and out of shul on Shavuos? On the first day, many people, even mothers and babies, came in to hear the reading of the Ten Commandments. On the second day, after the Torah reading, many children and adults went out before Yizkor.
Afterwards, during Mussaf, everyone came back in, and many fathers covered their sons with a tallis during Birkas Kohanim.
What is so special about Birkas Kohanim? Why are we so anxious to be there when the kohanim say it?
There is a good reason. Our parshah tells us that the kohanim are commanded to bless the Jewish people with a special prayer.
Prayer? Didn't we say it was a blessing? Is there a difference between a prayer and a blessing?
Actually, there is. Do you remember when Yaakov blessed his grandchildren, Menasheh and Ephraim? Ephraim, the younger one, received a bigger blessing. Was this Yaakov's own decision? No! He was only giving the blessings that HaShem had intended for both of those tribes.
A tzaddik's blessing helps a person receive what HaShem has in store for him. But prayer can add more. Prayer can change things and make things better. We pray for a sick person to recover and for a poor person to be given his needs. That's why our prayers say Yehi Ratzon, "May it be HaShem's will." This means that we are asking HaShem to be willing to give a person more than what He is giving him now.
Our Rebbeim explain that the blessings of the kohanim also have the power of prayer. The kohanim give us HaShem's blessing for a good life, for peace, and for security. At the same time, this blessing also works likes a prayer, bringing us even more than what was already in store for us.
(Adapted from Likkutei Sichos, Vol. X, Parshas Lech Lecha)