This auspicious occasion falls on Thursday, April 9, this year.
Here are two pieces written on this occasion from the website of the Leader of the Islamic Revolution Ayatollah Seyed Ali Khamenei’s office:
Imam Mahdi’s Birth Anniversary a Manifestation of Optimism about the Future
The 15th of Sha'ban is the embodiment of our hopeful outlook towards the future. All the hope that we invest in something may or may not have the outcome that we hoped for; however, the hope towards the final salvation by the absolute Wali [representative of God] of the Almighty God— the Imam of the Time (may God hasten his reappearance, and may our souls be sacrificed for his sake) — is an inviolable hope... It is not only Shias that have made this claim; it is not only Muslims that have made this claim: all religions of the world are waiting for such a day to come.
Our privilege is that we know him: we feel his existence; we believe in his existence; we speak to him; we address him; we make requests to him and he grants us our requests. This is the difference between us and others. Others —non-Shia Muslims and non-Muslim believers — believe in something that is vague; however, this is not the case with us Shi’as. It is clear what we want and whom we speak to. The 15th of Sha'ban is a day of hope.
Belief in the Savior a Component of Religions’ Worldviews
Belief in the Imam of the Time (may God hasten his reappearance) is a component of religions’ worldviews. That is, just as divine religions hold viewpoints within their general worldviews about the universe, mankind, origin and the end of human life’s trajectory—about genesis and resurrection—they also hold viewpoints in their worldviews about the final destination of the caravan of humans.
A worldview is a great system which lays the foundation for all the thoughts, obligations and rules of religions. It addresses the issues of the afterlife and the hereafter.
Another issue is where the mankind is heading to. If we liken the human community throughout history to a caravan which is taking a specific path, then we are faced with this question: Where is this caravan going? What is the destination of this caravan? What is the end of this path? This is a serious question and every worldview should answer it.
Religions have answered this question... all of them believe that this caravan will reach a favorable, sweet and pleasant destination in the end.
The main characteristic of this destination is justice. Justice has been humanity's general request from the first day until today and it will remain mankind’s main request until the end.
Those people who try to believe in variety, diversity and change in their principles and main philosophies cannot deny the fact that humanity has had certain requests from the first day until today, the most important of which is justice. Humanity is after justice. It has never changed its mind about this demand and in the end, this demand will be met.