According to our Sages, The Day of the Rain is as great as, or even greater than the day of the Giving of the Torah. The basis for this comparison is discussed in depth, as well as additional aspects of the connection between the rains and the Torah.
"R' Yochanan said: Three keys the Holy One blessed be He has retained in His own hands and not entrusted to the hand of any messenger, namely, the Key of Rain, the Key of Childbirth, and the Key of the Revival of the Dead"
In the land of Israel, one must constantly be aware of God's providence, for it is a land dependent on rainfall. This is what makes the land of Israel so special: Here, we must ascend spiritually and pray to God in order to merit the blessing of rain.
The physical world exists via two channels of relationship with the Creator of the Universe, through rain and through dew, and it is possible to look at the spiritual existence of Israel as existing on a kind of parallel with these two channels.
The Jewish people transcend the ministering angels and they do not need to have their prayers brought before God's glorious throne by them. The High Priest's presence in the Holy of Holies gives expression to Israel's exalted glory and greatness.
Most of us are familiar with the episode of Naboth's Vineyard or Elijah's dispute with the prophets of Baal. What is less known, however, is the background to the dramatic occasion in which Elijah decreed the stoppage of rain in the days of Ahab.
The entire purpose of rain and earth is to aid man, to provide him with life in order that he be able to fulfill his role in the world - “Without either, man could not exist.” On the other hand, the earth and the rain are immaterial without man.
We find that in his short prayer on Yom Kippur, the High Priest did not mention at all the spiritual needs of Israel, like Torah study or fear of Heaven. All that he says during his few moments inside the Holy Sanctuary is a short prayer for rain.