It is said in Mishnah (Ta’anit 26:2): There are no happier days for Israel than the 15th of Av and Yom Kippur (the Day of Atonement) for on them the maidens of Jerusalem used to go out dressed in white garments, borrowed ones, however, in order not to cause shame to those who had none of their own… and thus the maidens went out and danced in the vineyards, saying: ‘Young men, look and observe well whom you are about to choose?’
The pretty ones among the maidens, what did they say? "Regard but beauty alone because a woman is made for beauty." Those from the noble families among them, what did they say? "Rather look to a family for a woman is made to bear children." The wealthy ones among the maidens, what did they say? "Look at those with considerable wealth." The ill-favored ones among them, what did they say? "Take us for the glory of Heaven and crown us with the golden adornments."
The “ill-favored maidens of Jerusalem” is the last phase of Malchut, Dalet-de-Dalet, called “poor and wretched.” A person runs away from a work like this, having no motivation or desire for it because all this work is by “faith above reason.” But it is created this way on purpose to help one attain spirituality.
A person has to understand that if his egoistic desire doesn’t work any more, if he lacks any desire at all, or if the beauty or fulfillment doesn’t attract him any longer, then it is a sign that he needs another type of “fuel.” A person is given the chance to imagine a state in which he isn’t “bribed” by his egoism and to understand that if he continues working in the same manner, it will be “for the sake of bestowal.”
However, where does he get “anti-fuel” that will allow him to work without energy or fulfillment of his egoism? This is the state where a person starts to comprehend that he needs the Creator’s help. If he doesn’t get power from Above called the Light, he won’t be able to move at all. If someone wants to reach bestowal without being compensated by “wealth,” “beauty,” or “nobility,” but rather chooses a “poor and wretched wife” (according to an estimation of his own egoism), that is, if he chooses to bestow unconditionally, then he arrives at The Day (property of the Light) of Joy and Love (15th of Av).
From the 2nd part of the Daily Kabbalah Lesson 7/26/10, Article “15th of Av”