If you return, O Israel ... you shall return unto Me (Jeremiah 4:1).
Today is the first day of Elul, a period of time which is particularly propitious for teshuvah, for it precedes Rosh Hashanah, the Day of Judgment.
The Sages say that the Hebrew letters of the word Elul, form an acrostic for the verse in Song of Songs: I am devoted to my Lover and He is devoted to me (6:3). Song of Songs utilizes the relationship between a bridegroom and his betrothed to depict the relationship between God and Israel. Any separation between the two causes an intense longing for one another, an actual "lovesickness" (ibid. 2:5).
The love between God and Israel is unconditional. Even when Israel behaves in a manner that results in estrangement, that love is not diminished. Israel does not have to restore God's love, because it is eternal, and His longing for Israel to return to Him is so intense that at the first sign that Israel is ready to abandon its errant ways that led to the estrangement, God will promptly embrace it.
Song of Songs depicts the suffering of Israel sustained at the hands of its enemies, and we can conclude that the Divine distress at this suffering of His beloved Israel is great. Teshuvah is a long process, but all that is needed for the restoration of the ultimate relationship is a beginning: a sincere regret for having deviated from His will, and a resolve to return.