In the middle of the Parsha, Hashem says to Moshe to go tell Aharon and his sons to bless the people and say "יברכך ה' וישמרך. יאר ה' פניו אליך ויחונך. ישא ה' פניו אליך וישם לך שלום," "May Hashem bless you and safeguard you. May Hashem illuminate His face towards you and be gracious to you. May Hashem turn His face to you and establish peace for you"במדבר ו:כ"ד-כ"ו( ). These three Pesukim constitute what is commonly known as Birchas Kohanim. Rashi comments that this commandment includes the requirement that Aharon and the Kohanim should speak loudly so that everyone will be able to hear, that they should speak clearly and not talk fast, and that they should clearly give the blessing with good intentions. Even though Hashem tells Aharon and the Kohanim to bless the Jewish people, it is really Hashem who blesses them, because the last Posuk about Birchas Kohanim (שם פסוק כ"ז) concludes with the words "ואני אברכם," "And I will bless them." The Kohanim are therefore only the vehicles to deliver Hashem's blessings.
The first of the Berachos asks that Hashem should bless the people with wealth, as explained by Rashi, and long lives, as explained by Ibn Ezra, and protect them so that no criminals should come and cause them harm, because Hashem is the one who protects the Jewish people. The second Beracha is that Hashem should be pleased with the person; this symbolizes the attainment of spiritual growth and closeness to Hashem. The third Beracha is that Hashem should control His anger even when He is very angry at people for committing sins, and should let them have peace, which is the Beracha that includes all other Berachos. There is an interesting Halacha in regards to the recitation of Birchas Kohanim. The Kohanim go up to where the Aron is, and they then turn around and face the people, rather than facing the Aron. Normally, we daven to Hashem by facing towards the Aron, but the Kohanim here face the people. Why is this so, especially if, as mentioned above, the Kohanim are really only asking Hashem to bless the people? The answer is that when the Kohanim are blessing the Jewish people, they must be facing the Jewish people. When a person blesses someone else, he must look at him face to face. This makes the experience a more personal one, because the Kohein, in this case, is not simply reciting a general blessing without caring who the recipient is, and the people are not just receiving a blessing from an anonymous source. There is a personal connection which makes the Beracha more meaningful, and it symbolizes the fact that Hashem Himself is looking at us at all times.