The leaders of Israel, the heads of their fathers' household, brought offerings... (Num. 7:2)
This week's Torah portion describes at length the offerings of the Nesi'im (the leaders of the tribes) on the day that the Mishkan was inaugurated. Every Nasi offered the same offering. The Torah describes each Nasi's offering separately in virtually identical verses. Why could the Torah not simply mention the offerings the first time and then just say that the other Nesi'im brought the exact same offerings?
A man was once on a speaking tour and prepared long and hard for his first speech. The speech was entertaining and engaging - a big success. The next night he was scheduled to speak in another town, and he planned on giving the same talk. He was about to begin speaking when he noticed that some of the people present had heard him lecture the night before! He couldn't possibly give the same speech, so he quickly put a couple of ideas together and came up with a new one. However, it didn't compare to the previous night. After the speech he approached the repeat customers and apologized for not giving them a well-prepared speech. Disappointed, they replied, "You don't understand. We enjoyed last night so much that we came back to hear the same exact speech; we didn't want to hear a different one!"
The Torah is telling us that each Nasi who brought a sacrifice - even though it was identical to the previous Nasi's - in God's eyes it was like the first one he received. The sacrifice of every single Nasi was special to Him.
Sometimes we may feel that we are constantly doing the same exact thing over and over again, whether the prayers that we say day in day out or the mitzvos that we perform, and we may lose that initial enthusiasm. However, we must realize that every time we perform our duty God takes pleasure in it as if we had never done it before.