The Puran says that the person who keeps on chanting and chanting this Mantra in each and every moment of his life, whether he is eating, sitting, sleeping, standing, running or even falling on the ground, he will never touch sins and will always remain a sinless soul. - Ashok Mehta
The Mantra is ।। ॐ हरये नमः ।। - || Om Haraye Namah || and it has been taken by me from the Brahmand Puran.
Other than this, the Puran also says that the person who keeps on chanting this Mantra on and on, his wealth and assets increase and he gets the Punya of going to various Tirths[Important Hindu Places of Pilgrimage].
It is also said that the person who keeps on chanting this Mantra never goes to Narak after death.
People who don't have time to do Mantra Sadhana and want to achieve Bhog and Moksha at the same time must definitely introduce this Mantra in their daily lives.
Note- This Mantra is also a part of the devotional and most powerful Sandhya or Dusk Time Mantra, which is chanted daily by many devote followers of Hindu Mantra Vidya. The Mantra has also been attributed as one of the names of Vishnu, this Mantra can be seen here – Sandhya Dhyan Mantra