וְאַתֶּם תִּהְיוּ לִי מַמְלֶכֶת כֹּהֲנִים וְגוֹי קָדוֹשׁ "And you shall be for me a kingdom of priests and a holy nation" (Shemoth 19:6). Rabbenu the Alsheikh says that we can consider G-d to be like a king who has two groups of servants. The first group's responsibilities are to serve G-d within the confines of the palace. They never have any need to go out. Their reward for serving in the palace is simply the honor and privilege of being able to serve the king.
The second group's responsibilities are very different. They must take care of the king's matters and affairs outside the palace. They have to carry out the king's requests, but once they have completed what is required of them, they return to the palace. From that point on, they do not leave, but remain in the palace and receive great honor, all the while being close to the king.
The first group are the Malakhei HaShareth (Ministering Angels), who carry out G-d's Will. The second group are the Jewish people. Our mission is what is required of us during the time we are given on this earth. When we are called to return to Him, we can enjoy the peace and tranquility there, because our good deeds on earth created good angels. These angels are called the crowns on our head. Unlike human beings, angels have no evil inclination (Yeser Hara') and, therefore, cannot be rewarded for subduing it. Human beings, on the other hand, can elevate themselves by fighting the evil inclination and thus become "a holy nation".
(See Alshikh on the Torah, Parashath Yithro)
Yitro, Yisro, Yithro, Jethro, Parsha, Parasha