Why Do We Cry on Imam Hussain (AS) ??

By the Grace of the Almighty, the month of Muharram has come upon us again; the month of mourning for our beloved Imam Hussain and his family and friends (peace be upon them all). A question that is often asked each year is: why should we cry over something that happened over 1400 years ago? We are also faced with claims that crying for the beloved grandson of the Holy Prophet of Islam is bid'a (innovation). However, numerous hadith clearly show us that there is in fact nothing wrong in crying for Imam Hussain, which are narrated in the very books of those who claim it to be bid'a. (Sahih Tirmidhi; Mishkat al Masabih, hadith no. 6157)
Abdullah Ibn Abbas narrated, "One day at midday I saw in a dream the Prophet dishevelled and dusty, with a bottle containing blood in his hand. I asked, 'You for whom I would give my father and my mother as ransom, what is this?' The Prophet of Allah replied, 'This is the blood of al-Hussain and his companions which I have been collecting today.' Ibn Abbas said he had been reckoning at that time and discovered that it was then that Hussain had been killed.'" (Musnad Ahmad ibn Hanbal; Mishkat ul Masabih, hadith no. 6172)

Both of these narrations have been told from dreams, and some might object that perhaps it means they are not as reliable, but as narrated by Anas in Sahih Bukhari (v. 9, p. 104, hadith no. 122), "The Prophet said, whoever has seen me in a dream, then no doubt that he has seen me, for Satan cannot imitate my shape." In both of these narrations, our Holy Prophet seems very upset, and his own wife wept as the first hadith states. Therefore we can see that there is no wrong in crying for our Holy Prophet's beloved grandson.
Not only mankind was affected by the tragedy of Karbala, but we see in numerous hadith in both the Ahle Sunnah and Shi'a sources that the heavens and the earth also wept over Imam Hussain, and that the Jinns too mourned his death (Majma al-Zawaid, v. 9, p. 199, hadith no. 15179). Imam Ibn Jareer Tabari in his Tafsir Tabari (v. 22, p. 33) and Wahabi scholar Nawab Molvi Siddiq Hasan Khan Bhophali in Tafseer Fatah ul-Bayan (v. 8, p. 326) stated, "Al-Seddi said 'When Hussain bin Ali was killed, the sky started weeping for him; the weeping of the sky was by turning red.'"
Even with proof, some wonder why it is necessary to cry, and wonder how it will help us.Tears for the sake of Allah are known for softening the heart and purifying it form hypocrisy. Crying because we feel the pain of our Prophet and how he must have felt at the sight of his beloved grandson being killed can only increase our love for him and our love for Allah, while intensifying our hatred towards injustice and the need to fight against it with our pens, tongues and through our actions.
Our beloved Prophet has also said, "Hussain is from me, and I am from Hussain." (Narrated in numerous sources including Musnad Ahmad Ibn Hanbal, v. 4, p. 172; Al Tabarani, v. 3, p. 21; Mishkat al Masabih, hadith no. 6160.) So if Hussain is from our Prophet and he is from Hussain, then whose blood did the oppressors spill on the battlefield of Karbala? And if it was the blood of our Prophet running through the veins of al-Hussain, should we not cry for his tragedy?
The Holy Prophet himself has affirmed the reward for those who weep for Imam Hussain: "Whoever on the day of Ashura weeps for my son Hussain, Allah will place that person in Paradise alongside the Ulul Azm Prophets." (Isaba, v. 1, p. 226)