When the heart and soul are pure then the real “Kirtan” – God’s praises – is heard inside your own body. This inner kirtan never stops and is called “Akhand Kirtan”. It never stops. It is continuous and forever. It is heard in the tenth door (Dassam Duaar - Panch Shabad Anhad Naad). Once the spiritual heart (Hirda) becomes as pure as Akal Purakh Himself, as truthful as Braham Himself, then this continuous divine music (Akhand Kirtan) is heard. That was the dream of Dhan Dhan Guru Nanak Patshah Ji, and let us try and make it happen and turn this Kal-Jug to a Sat-Jug.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/spiritual-articles/20247-continuous-repetition-of-waheguru.html

Satnaam.info - 2. The Real Rules (Rehats)