Abu’l-Qasim ibn `Al’ al-Hamadany, the representative of Imam Imam Hassan Askari (a.s), received a document telling that our master, Grandson of the Holy Prophet (PBUH), Imam Hussein (a.s), was born on the third of Sha’aban; therefore, you should observe fasting on this day and recite the following supplication:
O Allah: I beseech You in the name of the one born on this day, the one promised with martyrdom before the beginning of his life and before his birth, the heavens and all their inhabitants wept for him; and so did the earth and those living one it; before his feet stepped on it; the mourned slain one; and the master of the Family (of Prophet hood);
and the one who shall be backed with victory on the Day of Return; the one whom has been awarded with the favor of the Imams’ being from his offspring as recommendation of his being slain; and the one awarded with the favor of the soil of his grave carrying cure; and the one awarded with the favor that he will be triumphing when he will be returned;
And also the Prophet’s Successors from his offspring will be returned after the advent of their Rising Imam and after his occultation, so that they shall take revenge, and they shall retaliate, and they shall please the Omnipotent Lord, and they shall be the best supporters.
May Allah’s blessings be perpetually upon them whenever night and day succeed each other.
O Allah: I thus beg You in the name of them; and I implore You with the imploration of a sinful one who confesses of his guilt, and who has done evil to himself, due to his violations—the past and the present.
He thus beseeches You for protection from You up to the place of his grave.
O Allah: (please) send blessings upon Muhammad and his Offspring, and include us with his group (on the Resurrection Day) and allow us to dwell in the House of Honor with him, and in the abode of residence.
O Allah: as You have conferred upon us with the honor of our recognition of him, (please) confer upon us with the honor of being near to him, and bestow upon us with the bliss of accompanying him and enjoying a close rank to him, and include us with those who submit to him totally, and those who pray (You) for sending blessings upon him whenever they mention him, and also upon all his Successors and Selected Ones, whom are defined by You as twelve persons, being the luminous stars, and the Arguments against all humankind.
O Allah: and (please) grant us on this day the best of grants, and make all our prayers on this day responded, in the same way as You gifted Hussein to Muhammad: his grandfather, and in the same way as the angels Future sought refuge with his (i.e. al-Hussein) cradle we are thus seeking refuge with his tomb after him (i.e. his martyrdom) as we are witnessing the soil of him and expecting his return.
Respond to us; O the Lord of the worlds.
After that, you may recite the Imam Hussein’s Dua’a, which is the last supplication uttered by Imam Hussein (a.s) when his enemies surrounded him in large numbers on the Day of Ashura (the tenth of Muharram, AH 61):
O Allah: You are verily the Elevated in position,
The Magnificent in omnipotence,
The Mighty in prowess,
The Self-Sufficient from the creatures,
The Ample in pride,
The Powerful over all that which You want,
The Close in mercy,
The Truthful in promise,
The Opulent in favors,
The Sympathetic in ordeals,
The Nigh when Your are prayed,
The All-encompassing of all that which You have created,
The Accepter of the repentance of him who repents to You,
The Powerful to do whatever You want,
The Taker in all that which You decide,
The Thankful for those who thank You,
The Rememberer of those who mention You.
I pray You for I need You;
And I desire for You for I am in want of You;
And I resort to You for I am terrified;
And I weep before You for I am distressed;
And I seek Your aid for I am weak;
And I depend upon You for I trust in none save You;
(Please do) decide between our people and us with the truth,
For they have deceived us, cheated us,
Disappointed us, betrayed us, and killed us.
We are verily the progeny of Your Prophet,
And the sons of Your beloved one,
Namely Muhammad ibn `Abdullah,
Whom You have chosen for the Divine Mission
And for keeping Your Revelation.
So, (please so) prepare a way out and a relief for us,
Out of Your mercy; O the most Merciful of all those who show mercy.
* Source: duas.org