Temporary and Permanent Holiness
Rav Kook connects the idea of קדושת שעתה, a temporary holiness, with קדושה לדורות, a sanctification for generations. He starts with comparing כהונה לשעתה and קדושה לדורות, the service of the Kohanim. Moshe Rabbeinu served as Kohein Hagadol during the week prior to the dedication of the Mishkan. His was a temporary service, while the service of Aharon as High Priest, was given to him for all generations. This includes the special role of the Kohanim until today.
This concept can be seen in other instances such as the showdown of Eliyahu Hanavi with the prophets of Baal at Mount Carmel. There was a temporary holiness given to that mountain that allowed Eliyahu to offer a sacrifice there. This was not as great as the eternal holiness of Mount Moriah in Jerusalem.
The giving of the Torah on Mount Sinai was a culmination of the exodus from Egypt. Its entire purpose was to receive the Torah on Mount Sinai.
The Sinai experience had both a temporary and permanent aspect to it. The temporary aspect was the magnificence of the moment. There was thunder and lightning and the entire nation heard G-d speak. The sanctification for generations was the message that was given for all generations. It represented the special destiny of the Jewish people and the role given to them at Sinai. The Jews were to live a spiritual life according to the dictates of the Torah. They were also given the task of teaching decency and morality to the world.
This is an important message for all of us. We must be clear as to what is permanent and what is temporary in our lives. This would save us a great deal of aggravation if we didn’t allow temporary annoyances to get us down. We must focus on the eternal aspects of our lives. The Torah and Chessed that we do, stays with us both in this world and the next. This is why Rav Kook felt that the sanctification for generations was greater than the temporary.