The book of Shir Hashirim (Song of Songs) is a love story between G-d and the Jewish people. It uses the metaphor of a man's love for his wife to describe G-d's love for the Jewish people. This analogy is significant, since it explains why G-d continues to love the Jewish people even when they sin against Him. The underlying love between a man and his wife restores harmony to the union even when they have a dispute. Similarly, G-d's deep-rooted love for the Jewish people maintains His relationship with them even when they rebel against Him.
Our Sages teach us that for several millennium, there has been a fundamental disagreement between G-d and the Jewish people regarding the process of teshuvah (repentance). The Jewish people proclaim, "Return us to You Hashem, and then we will return to You." In other words, we tell G-d to take the first step. G-d responds to the Jewish people, "Return to Me, and I will return to you." The Jewish people have to initiate the process of repentance.
The Gemara in Mesechta Berachos elaborates on the perspective of the Jewish people. It explains that the Jewish people really want to do G-d's Will. However, the evil inclination and the subjugation of the gentile nations of the world prevent them from doing so. Therefore, unless G-d brings the Moshiach, they will be unable to repent.
The prophet Michah foretold that G-d will send Elijah the Prophet to us before the great and awesome day of the Moshiach arrives. On that day, children will bring their wayward parents close to G-d, and parents will do the same for their wayward children.
This prophecy can be better understood in the context of the following story: A rebbe once instructed his chassid (follower) to find Elijah the Prophet in a certain dilapidated hut. The chassid followed his rebbe's instructions and found a poor widow living there with seven children. It was Shabbos eve at the time, and the chassid asked the widow whether he could spend Shabbos there. The widow invited him, but she disclosed to him that she couldn't afford to feed him. The chassid realized that the family had nothing to eat, so he took the initiative to buy groceries for them. For the first time in their lives, the family enjoyed a proper Shabbos meal. The spiritual atmosphere in the home that Shabbos made a profound impression on everyone who was there.
After Shabbos was over, the chassid returned to the rebbe and reported to him that he did not find Elijah in the house that he visited. The rebbe just smiled and sent him back to the same house on the following week. As the chassid approached the house, he heard the children complaining to their mother that they couldn't bear another Shabbos with nothing to eat. The mother replied to them that they have to pray for Elijah the Prophet to visit them again. Only then would their situation improve. At that moment the chassid realized that the rebbe was right all along. The rebbe was trying to tell him that he himself had the capacity to become like Elijah the Prophet.
In a similar vein, we all have to become like Elijah the Prophet. It is not sufficient to merely wait for the Moshiach to arrive. We have to actively bring it closer. We have to take the initiative to bring others and ourselves closer to G-d.
R' Yisroel Salanter once declared that in his youth he believed that he could change the whole world. As he got older, he realized that changing the world was too difficult for him to accomplish. Therefore, he focused his attention on changing his own country. However, that too proved to be beyond his capabilities. Instead he decided that he would change his own city. Once again, he failed to achieve his goal. Still later he attempted to change his own family, which also met without success. Finally, he realized that the only person that he had the power to change was himself. He worked on correcting his own character deficiencies, and when he did so he realized that the whole world changed along with him.
The purpose of this story is to demonstrate that teshuvah (repentance) is not about trying to change others. Rather, it is about changing ourselves through self-introspection. When we change ourselves, the whole world changes with us.