Authority of the Rabbis
There is a concept in Halacha that says, בית דין של מטה גוזר, בית דין של מעלה מקיים, “When the earthly court decrees, the Heavenly court fulfills.”
Specifically, this is mentioned in establishing the Jewish calendar. The Sanhedrin had the authority to decide if there would be an extra month of Adar. As Rabbi Tendler put it, “They will decide if we are eating Matza on the fifteenth, or Hamantaschen.”
This is more than just giving authority to the Rabbis to decide matters of Jewish Law. Their decisions fall under the general category of the תורה שבעל פה, the Oral Law given at Sinai.
This was the point made by the Chazon Ish. Even if one has perfected his character traits to the highest level, he might still be lacking an understanding and appreciation that the Halacha represents the highest level of truth in the world.
The Halacha originates with Hashem. The authority He has given to the Rabbis to decide matters of Jewish Law, makes these laws as if they came directly from Him. They are perfect and reflect truth and justice.
This is the ideal state we are supposed to accept. Admittedly, there are many who interpret the law in such an unappealing way, that it makes it difficult to appreciate the beauty and Divine aspect of these laws.
Somewhere along our long and bitter exile, the approach to Halacha was compromised. We must find teachers that will help get things back on track, so that all doubts related to the validity of Halacha will be eliminated. We will have no problem accepting that earthly, rabbinic decrees, are validated in Heaven.