Spirit of the Law: Halachos of the Three weeks I

Kitzur Shulchan Aruch: 121:1 "From the 17th of Tamuz the tzaros of the churban started so the custom is to comport oneself a little like a mourner. It is fitting for anyone who fears heaven to say tikun chatzos after midday during this time…"
The Gemara writes:all who mourn the destruction of Yerushalayim will merit to see her nechama .The Maharal explains two reasons why one must first mournto see the nechamah.

the first thing to understand is that the world is in a very imperfect state primarily because it lacks its most basic component: the Beis Hamikdash.Mourning the Beis Hamikdash shows that we appreciate our loss and the reason for our loss.
The more we appreciate how much we lack on because of our lack of a Beis Hamikdash the more we mourn and show our relationship with the true metsios of the world. For the world is really supposed to be a world of completion for a world with a Beis Hamikdash reveals the deep spiritual connection between the Creator and His creations .
The second reason is because the rule is that only something lacking can come to a new level of completion. For example, a seed must decompose in order to grow into a tree. The contents of an egg must become putrid before a chick can be formed.
We can learn this from a number of chazal’s as well: The yearning for Chachma makes one a suitable vessel to receive chachama. A woman’s yearning for children makes her a suitable vessel to have children. Even in the antecedents of the world we find that first there was tohu, vohu and choshech and only then could there be a creation.
For this reason it is only one who feels that he is missing the Beis Hamikdash who will be able to access the spiritual levels of nechama, Hashem's comfort to us. Only one who truly knows his flaws has space to become more complete. One who feels complete cannot develop since “you can’t improve on perfection.” If he really doesn’t feel perfect why doesn't he yearn for completion? Failure to yearn shows that for one reason or another we relate to ourselves as if we were perfect . Intenllectual knowledge of our flaws is completely irrelvant just as one who "knows" that he needs to control his temper will continue to act the exact same way if his knowledge stays in his head and does not reach his heart.
Our identity is revealed in our attitude. Refusal to emotionally acknowledge our imperfections by ignoring them and failing to yearn to improve them, condemns us to bear our faults.To explain this with a simple metaphor:if someone who takes a daily dose of live saving medicine knows he has run out he can try and get another prescription and purchase more. One who has no idea that he is almost out believes he has enough and will take no steps to rectify his situation until he notices that his supply is dwindling. Surely we would never fix something we don’t believe is broken.
Often one doesn't yearn to improve his faults because he feels that his flaws and sins are so much a part of him that he will never change. This person also belives he is complete but in a different way. He feels that he is complete in the sense that he cannot possibly change so why yearn? If we really felt there was hope because Hashem can always improve us, we would yearn to access the levels of the holiness of the Beis Hamikdash continuously with our whole heart.
In Brochos 32 we find that for although we no longer have the holy temple, regarding one who has true understanding the Beis Hamikdash is considered to have been rebuilt.If we yearn and plead with Hashem to improve our faults we will surely attain the level of completion Hashem wants for us. The first step of all spiritual ascent is an absolute belief that all failures can be turned around. All one needs to do is yearn to improve with his entire being whenever he can. One must also "tough it out" by patiently doing whatever good possible while waiting for Hashem's salvation.
Rav Nosson of Breslov zt”l, wrote in a letter, “...Regarding the all important issue: your very bitter cry of pain (of your present spiritual state) as a result of your of sins and the thoughts that the Yetzer Hara attacks you with,the main tactic of the yester Hara, (since all illicit actions are the fruit of negative or unproductive thoughts which determine our attitudes and spiritual\ emotional state as well as how we will react.Bad thoughts are the prelude to all spiritual falls.) I have heard your cries and know your pain from before and now (so much that) my heart goes out to you since I feel every bit of your pain as if it was my own…but the very fact that you are crying out with such bitterness, literally until the heavens because of this, comforts and encourages me!
My son; you must know and believe that Hashem hears every single cry and will surely deliver you in the merit of following the advice of the true tsadikim. That the deliverance is taking so long is on account of a hidden reason. But it is certain that failing to strengthen ourselves to overcome such bad thoughts is partially why your deliverance tarries.)
Another reason this [often] takes so long is because Hashem loves to hear the tefilos of Yisrael, even the prayers of the lowest of the low! But even so; not even a single cry is lost so regardless of results, you must continue to cry out with all your might!
… Know my son:there were people much worse off than you that I knew who were healed. Through the words I received from the Rebbi, they were completely rectified and their lot is the portion of those who merit eternal life… !
In another letter Rav Nosson signs off by saying, “May Hashem help us to weep and mourn the destruction of the Beis Hamikdash which principally means that we should mourn because of our sins that prevent the rebuilding of the Beis Hamikdash until we merit to change our agony and sighing into the happiness and joy of trust in Hashem’s kindness and great deliverance until everything turns into good!
The words of your father, who is waiting for deliverance and praying for you,
Nosson of Breslov .
This sentiment was echoed by Rav Wolbe, zt”l, when he said, “I will give you a big sum of money if you can find even one bochur who believes that it is possible to come to the level whereby one can go an entire year without sins. I am not talking about trying to accept upon ourselves to go a year without sin. Quite the contrary! Kabalos have to be exclusively small. But we must at least believe that this is possible (after much introspection and toil.) I am not even talking about coming to gadlus which is a much greater level. I am talking about entering into our heads and hearts the genuine belief that it is possible to rid ourselves of all sin! This emunah is a prerequisite of true [teshuvah which consists of] charata of the past and acceptance for the future !”