The month of Adar in the Beit Hamikdash was a very busy time. There was an active collection going on in the whole country. Every male above the age of twenty, needed to contribute a half shekel. This money was used for the maintenance of the Temple. In addition, the גזבר, or Temple treasurer, needed to make sure that all of the half shekels of the previous year, were used up.
They needed to see what needed to be spruced up. This allowed them to use up the old funds, and have the Temple in tip top shape, for the massive pilgrimage to Jerusalem for Pesach. It is no coincidence that we read the double portions of ויקהל-פקודי at this time. It is mainly an accounting of where all of the donations towards the construction of the Mishkan, were used.
As leader of the Jewish people, Moshe Rabbeinu realized that he needed to set an example for future leaders. Despite his great piety, he wanted to give an explanation for all gifts that came to him. He needed to prove that there be no suspicion that he took any of these donations for his personal use.
While in many ways, Adar was the accounting season of finances, it was also a time when everyone needed to look at themselves, and be certain that they were conducting their lives with honesty and integrity. After all, we must prepare for the major accounting we will need to give, when we leave this world when we reach 120.