Ibn Hazm says:

95. In times of civil war, the blossom does not set fruit.

Notes:

• I tried to understand exactly what Ibn Hazm meant by this line for a while now. As poetic as it is, it remains vague. But recently, I think I know what he was aiming at.
• Often we see brothers or sisters who are deeply involved in Islamic activites. They may be often at your local masjid, they may be running your MSA, they may be the best recitors of the Qur'an, they may be the one's known to pray in length, or fast with intensity - but then one day, in what seems to be a blink of an eye - they've completely changed. Their beard or hijab has disappeared, and now they're only known for their involvement in haram - in our culture, often their involvement with the other gender.
• Here people often ask "how can this happen to them" or the more arrogant version of the question posed, sounds as "how can Allah do this to them".
• What needs to be understood is that Allah intensifies the disease of misguidance in the hearts of those who have already chosen misguidance. And so Allah (swt) says:
  فِي قُلُوبِهِم مَّرَضٌ فَزَادَهُمُ اللّهُ مَرَضاً
  {In their hearts is a disease (of doubt and hypocrisy) and Allah has increased their disease.}
• The reality is that, the deeds they did that we thought were good, bore no fruit. They were essentially meaningless because there was a lack of sincerity and a misdirection of intention. And so within this person there is a civil war, where the outerward reality of the person belies their inner reality. This is where hypocrisy is born. This hypocrisy causes massive pain within the person, which drives them to eventually just not care about their honour or their reputation or anything like that, and begin to outwardly sin in some of the most shameful ways.
• But during this time of "civil war", which all of us live through at some point or another, there is no good that can come out of your actions. There is no fruit that can blossom. Until you can return sincerity to your heart, all your good deeds become exercises in futility.
• This is the importance of tazkiyyah, self-purification. It is needed before anything else in order to give value and bring benefit from your good deeds and righteous actions.
• You can see this fact in Surat al-Baqarah, where Ibrahim (as) makes dua to Allah and says:
  
  رَبَّنَا وَابْعَثْ فِيهِمْ رَسُولاً مِّنْهُمْ يَتْلُو عَلَيْهِمْ آيَاتِكَ وَيُعَلِّمُهُمُ الْكِتَابَ وَالْحِكْمَةَ وَيُزَكِّيهِمْ إِنَّكَ أَنتَ العَزِيزُ الحَكِيمُ
  {"Our Lord! Send amongst them a Messenger of their own (and indeed Allah answered their invocation by sending Muhammad Peace be upon him ), who shall recite unto them Your Verses and instruct them in the Book (this Quran) and Al-Hikmah (full knowledge of the Islamic laws and jurisprudence or wisdom or Prophethood, etc.), and sanctify them. Verily! You are the All-Mighty, the All-Wise."}
  
  Twenty-two verses later, Allah (swt) states his acceptance of Ibrahim's (as) dua
  
  كَمَا أَرْسَلْنَا فِيكُمْ رَسُولاً مِّنكُمْ يَتْلُو عَلَيْكُمْ آيَاتِنَا وَيُزَكِّيكُمْ وَيُعَلِّمُكُمُ الْكِتَابَ وَالْحِكْمَةَ وَيُعَلِّمُكُم مَّا لَمْ تَكُونُواْ تَعْلَمُونَ
  {Similarly (to complete My Blessings on you) We have sent among you a Messenger (Muhammad SAW) of your own, reciting to you Our Verses (the Quran) and sanctifying you, and teaching you the Book (the Quran) and the Hikmah (i.e. Sunnah, Islamic laws and Fiqh - jurisprudence), and teaching you that which you used not to know.}
  
  This dua' is basically outlining the job of a Prophet and Messenger. The point of interest to be taken from this is that, look at how when Allah accepted the dua', He brought mention of tazkiyyah (sanctity) as the first job of the Prophet, because it is needed as the first step of the worshipper.