In 28:29-30 the passuk tells us, " וְנָשָׂא אַהֲרֹן אֶת-שְׁמוֹת בְּנֵי-יִשְׂרָאֵל בְּחֹשֶׁן הַמִּשְׁפָּט, עַל-לִבּוֹ--בְּבֹאוֹ אֶל-הַקֹּדֶשׁ: לְזִכָּרֹן לִפְנֵי-ה', תָּמִיד...וְנָתַתָּ אֶל-חֹשֶׁן הַמִּשְׁפָּט, אֶת-הָאוּרִים וְאֶת-הַתֻּמִּים, וְהָיוּ עַל-לֵב אַהֲרֹן, בְּבֹאוֹ לִפְנֵי ה'; וְנָשָׂא אַהֲרֹן אֶת-מִשְׁפַּט בְּנֵי-יִשְׂרָאֵל עַל-לִבּוֹ, לִפְנֵי ה'--תָּמִיד" - And Aaron shall bear the names of the children of Israel in the breastplate of judgment upon his heart, when he goeth in unto the holy place, for a memorial before the LORD continually. And thou shalt put in the breastplate of judgment the Urim and the Thummim; and they shall be upon Aaron's heart, when he goeth in before the LORD; and Aaron shall bear the judgment of the children of Israel upon his heart before the LORD continually.
The passuk tells us two issues about Aharon carrying Bnei Yisrael on his heart. Once about the names and once about their concerns.
The names of Bnei Yisrael indicate something personal. Aharon has to think about every Jew all the time. Whenever he goes into the Holies, he must have the welfare of every individual Jew in his heart.
The judgement of Bnei Yisrael refers to the concerns of the people. When Aharon goes into the Holies, he must bring with him the worries and concerns of the people.
The act of Aharon (or any Kohen) entering into the Holies and performing the obligations, is not a power trip, nor is it an act limited to the benefit of himself or the nation on some sort of macro level. Aharon must have at the top of his concerns the needs, the worries, the concerns of every individual Jew.
That is a lesson for anybody in leadership positions. You are there representing the people. You are not in place in order to personally benefit, though that might very well be a result of such positioning. You are there in order to look out for the needs of the people. You are there to remember each person and his concerns, and you are to bear them on your heart at all times. That should be what drives and motivates you to act.