Mahalaya is considered to be an auspicious occasion for the people of Bengal and Bengalis. Observed seven days before the Durga Puja, it marks as the advent of Durga, the goddess of supreme power. It is the period when Pitri Paksha (Shola Shraddha or food offering) ends giving way to Devi Paksha (Goddess Period). Mahalaya is thus referred as a kind of invocation or invitation to the mother goddess to descend on earth - "Jago Tumi Jago". This is done through the chanting of mantras (hymns) and singing devotional songs.
Mahalaya is also considered to be the day of remembrance. On this day, devotees gather by the banks of river Ganga, clad in dhotis to offer prayers to their demised forefathers and relatives and take holy dips. This ritual starts off from pre-dawn hours and it continues till midday. This whole ritual serves as a most integral part of Mahalaya. Another faith which is also closely associated with the day is that Goddess Durga is invited to her parental home. Her homecoming heralds the most famous festival of this place which is the Durga puja, a four day long festival.
Much before sunrise, to be precise at 4 p.m. devotional song "Mahisasura Mardini" or "The Annihilation of the Demon" is played by the All India Radio which serves as the invocation to the Goddess, in the magical voice of Great Birendra Krishna Bhadra. The way "Mahisasura Mardini" is depicted through his recitations is just irreplaceable. Without listening to his magical chants, Durga Puja celebration in Bengal and for Bengalis is incomplete. As the recital begins, the serene morning air resonates with the long drawn sound of the sacred conch shell, immediately followed by a chorus of invocation, melodiously setting the stage for the recitation of the Chandi Mantra.
The story element of "Mahisasura Mardini" is very enthralling. It speaks volume about the increasing cruelty of the demon king Mahisasura, against all Gods and Goddesses. Unable to bear his tyranny further, the gods plead to Vishnu to annihilate the demon. The Trinity of Brahma, Vishnu and Maheswara (Shiva) come together to create a powerful female form with ten arms - Goddess Durga or 'Mahamaya', who embodies the primal source of all power. The Gods then bestowed their individual blessings and weapons upon this Supreme creation. Armed like a warrior, the Goddess rides a lion to battle with the Demon King. After a stern combat the 'Durgatinashini' is able to slay the 'Asura' king with her eternal powers. Finally heaven and earth rejoice at her victory.
Apart from this story element, several other connotations are being attached to the concept of Mahalaya. According to the Puranas on this day, Lord Rama worshipped Devi Durga before departing for Lanka to rescue Devi Sita from the clutches of the demon Ravana. Traditionally Durga Puja used to be performed in the spring time by King Suratha. That is why it is also known as Basanti Puja. But Lord Rama worshipped Devi Durga in autumn unlike traditions. From then onwards it came be known as Untimely Worshipping or ‘Akaal Bodhan'. Akaal Bodhan because the time Lord Rama worshipped Devi Durga at the time God and goddess were in awakened state.
Another mythical incident which elaborates the concept of Mahalaya further is the story from the Mahabharata period. It is believed Karna used to donate gold and other wealth to people. For his charitable nature, he was also known as Data Karna. So after he died, due to his good works done back on earth, he got back those in thousand fold in heaven. Karna's soul was hungry by then and asked for food but he was served by gold and silver. He got frustrated and asked the god of death Yama, the reason behind. To which Yama replied throughout his whole life he had only donated gold and silver but never donated food to anyone even to his ancestors. Astonished, Karna fed the poor people and made offer to his forefathers. So after 14 days, he returned back to heaven and was served by huge amount of food. So these 14 days are honored as the Mahalaya period.
"Ya devi sarbabhuteshshu, sakti rupena sanksthita Namasteshwai Namasteshwai Namasteshwai namo namaha." Thus with this final chant ends the process of invocating the Supreme Goddess to descend on this valley and marks as a beginning to celebration, for her final arrival.