It is a long tradition that one reads the Devi-Bhagavatam or the Devi Mahatmyam (Durga saptashati, 700 verses on Durga) during Navaratra to invoke the blessings of Mother Durga. Devi Bhagavatam notes that Lord Rama meditated and fasted for nine days after Devi Sita was kidnapped by Ravana.
The reading of Durga Saptashati (Devi Mahatmyam) during Navaratri is to be done follows:
Chapter 1 (Madhu kaitabha samhaara) is to be read for 1st day,
Chapter 2, 3 and 4 (Mahishhasura samhaara) to be read on 2nd day,
Chapter 5 and 6 (Dhuumralochana vadha) on the 3rd day,
Chapter 7 (Chanda Munda vadha) on 4th day,
Chapter 8 (Rakta biija samhaara) on 5th day,
Chapter 9 and 10 (Shumbha Nishumbha vadha) on 6th day,
Chapter 11 (Praise of Narayani) on 7th day,
Chapter 12 (Phalastuti) on 8th day,
Chapter 13 (Blessings to Suratha and the Merchant) on 9th day
Chapter 14 (Aparadha Kshamaprarthana) on 10th day
