Elul is a time for drawing closer to Hashem. "The voice of my beloved" refers to these days. It is a form of intimacy and affection, of familiarity. Everyone learns this fundament already in cheder, without realizing all that it entails. One must know that the door is open during these days.
This vital foundation, of drawing close to Hashem during Elul, is discussed in Chayei Odom (Vol. II;138:1). He brings it from Pirkei deRabi Eliezer: "While Teshuva is beneficial at all times, nevertheless, during Elul it is enhanced, conducive and more attainable in that it is preferential over the rest of the year. These have been days of favor since the time of our nationhood. When Jewry sinned with the Eigel and the Luchos were shattered on the 17th of Tammuz, Moshe Rabbenu ascended Har Sinai, prayed and was commanded by Hashem to carve [new ones]. He was appeased and in Elul, he again ascended to Heaven, remaining there until Yom Kippur. These were days of favor and have been so ever since. This is why, year in and year out, during Elul, Hashem makes Himself accessible to Jewry, and despite the fact that they stumbled and sinned, He opens an entrance way for them once again."
Moshe Rabbenu went up Har Sinai after the infamous fall of the Eigel. A need to reestablish the Giving of the Torah became necessary and the Jews knew that Moshe Rabbenu was going back up to Heaven to receive the second Luchos. Hashem accepted Moshe's plea and since then, for all time, a wonderful thing takes place: during the month of Elul up till the time of the coming of Moshiach; these are days auspicious for Hashem's favor, renewing themselves each year once again.
But we must take note: The very fact that we become close to Hashem does not only stem from Elul; it is a veritable attribute of the Jewish people which incorporates all of their advantages, both as an entity and as for the individual. "For who is like unto to such a mighty people who possess a G-d Who is close to them at all times when they cries out to him" (Devorim 4:7).
