Some of our hadith sources contain hadiths narrated from the ma'sumin mentioning how Allah (swt) sent help for Imam Hussein by the jinns and angels.
Of course, this isn't something unusual and has happened before; jinns, angels and any other means of help have been sent down by Allah for the Prophets. In the Quran, Allah (S.A.) says: "Thus (remember when) you (all) implored your Lord (in the battlefield of Badr), so He responded to you:" I will reinforce you with a thousand angels riding up one after another."
Some of the main reasons why Imam Hussein didn’t accept any kind of help are that: the only way he could bring reform to the Ummah in his day was through his martyrdom, he had a great urge and desire to return to his lord, it was his destiny for him to be martyred, the Imam for a fact, conceived martyrdom as the greatest and most pleasant way of dying and wanted to execute this divine plan exactly the way Allah wanted and in a natural way, without the intervention of other beings.
Divine aid for Imam Hussein (as):
In our hadith sources, we can find a few hadith narrated from the Ahlul-Bayt regarding Allah's assistance to Imam Hussein by sending him an army of jinns and angels. For example, Sheikh Mufid has narrated this hadith, through a set of narrators, from Imam Sadeq: "At Imam Hussein's departure from Medina, a group of angels and a group of Muslim and Shiite jinns came and offered their help, but the Imam replied: "May Allah bless you, but I am responsible for my own duties and the time and place of my death has been determined.” The jinns said: "If you had not forbidden us, we would have wiped out all of your enemies." In response Imam Hussein said: "We are more capable of doing so ourselves, yet we refrain, so those who are go astray, go astray with an ultimatum, and those who go on the right path, do such out of awareness and with clear reason." Similarly Imam Sadeq (A.S) says: "My father said: When Imam Hussein (A.S.) confronted Umar Ibn-Sa’d and the battle commenced, Allah sent his aid to the imam, to the extent that it cast its shadow on him, and at that moment he had the option to choose between triumph over his enemies or meeting Allah, and he chose to return to Allah."
Likewise some hadith state that a number of angels came to help Imam Hussein (A.S.). The first time they came the Imam didn’t give them permission to participate in the battle and when they came for the second time the Imam had already been martyred. For example, take this narration from Imam Sadeq: "Four thousand angels descended to fight with Imam Hussein, but they were not given permission to battle. Once more they were given permission but it was too late and the imam had already been martyred..."
To sum it up, this story can be found in our ahadith and is considered true and no scholar or religious expert has tried to deny it; because it isn’t contradictable to any Islamic principle. The assistance of jinns and angels by the demand of Allah has happened for the Prophets also; Allah (S.W.) says in the Quran: "Thus (remember when) you (all) implored your Lord (in the battlefield of Badr), so He responded to you:" I will reinforce you with a thousand angels riding up one after another." Or like when they helped the Muslims in the battle of Ahzab, although in some cases they weren’t able to help due to a few reasons that will be mentioned.
Why didn’t Imam Hussein accept the jinns’ and angels’ offer to help?
In response we can mention the few following reasons:
1. Considering the complicated political situation that Muawiyah and Yazid had created, the wrong they would do in the name of Islam, and also the fact that distinguishing wrong from right had became really difficult, the only way to stop this situation and revive Islam was the martyrdom of the Imam, his children and his companions.
2. The ahadith regarding this matter indicate that the Imam was destined to be martyred so he could achieve his ultimate purpose which was awakening the ummah and saving them from ignorance.
3. Imam Hussein believed that martyrdom was the most beautiful and honorable death possible. This fact has been verified in the sermon that he gave on his departure from Mecca to Iraq: "The adornment of death for mankind is like the adornment of a necklace on the neck of a girl." meaning that death isn’t a restriction imposed onto one, but rather like a necklace; it is something cherished and valuable. Why not wear this necklace, and for Allah’s (swt) sake at that?! Dying for the sake of his religion was very pleasant and like honey for the imam (as). Martyrdom isn’t a flaw or deficiency that one needs to ask the angels for help from, it is a high and great quality; just like how Prophet Ibrahim (A.S.) saw martyrdom as an excellence and as a result wasn’t afraid of burning in the fire and didn’t ask Jibraeil for help, all he would do when they were catapulting him into the fire was remember Allah (swt) and call him.
4. Returning to Allah (S.W.) and his Prophets meant much more to Imam Hussein, especially with the governing circumstances at that time, than remaining in this world, as he mentioned in his sermon in Mecca: "My eagerness to meet my ancestors is like the eagerness of Yaaqub to meet Yusuf."
5. Even though the Imam was capable of succeeding over his enemies through metaphysical means such as miracles and in that case had no need of help from angels and/or jinns, he wasn’t willing to use miracles, for doing so for the Imam - who was to conform to the ordinary circumstances all humans must consent and adapt to - was in contradiction with what the imam was responsible to do, which was to do everything through natural means. In addition to that, one of the main reasons why Imam Hussein has had such a great impact on the lives of Muslims and all seekers of justice and freedom is the fact that he carried out his acts without using paranormal means but rather conducted based on common and standard circumstances. Leading his household to an unfair battle, them being taken as prisoners and all the disrespect they experienced, were all reasons that contributed to Imam Hussein's uprising becoming monumental and everlasting. Is there anyone who would actually think that the imam (as) couldn’t overthrow Yazid through supernatural means?!
 Allamah Majlisi, Biharul-Anwar, vol. 44, pg. 330.
 Seyyid ibn Tawus, Luhuf, pg. 141 (Farsi translation of Seyyid AbulHasan Mir AbuTalebi).
 Sheikh Saduq, Amaliyy (Farsi translation of Mohammad Baqir Kamare’i), pg. 638. It should be noted that this hadith has also been narrated in Kafi of Kuleini, see: Al-Kafi, vol. 1, pg. 283 and 284.
 See: Musbah Yazdi, Muhammad Taqi, Azarakhshi Digar az Asemane Karbala, pp. 44-66.
 Biharul-Anwar, vol. 44, pg. 329.
 Biharul-Anwar, vol. 44, pg. 366; Muhaddith Erbili, Kashful-Ghummah fi Ma’rifatil-A’immah, vol. 2 pg. 29; Luhuf, pg. 110 and 111.
 See: Javadi Amoli, Abdullah, Shokufayiye Aql dar Partowe Nehzate Hoseini, pp. 28-30.
 Shokufayiye Aql dar Partowe Nehzate Hoseini, pg. 27.
 Biharul-Anwar, vol. 44, pg. 366; Kashful-Ghummah vi Ma’rifatil-A’immah, vol. 2, pg. 29; Luhuf, pp. 110 and 111.