The taste of food or of anything eaten cannot be grasped if the person is ill or even if the mind is immersed in something else. So also, even if one is engaged in Namasmarana, Bhajan, Japa or Dhyana, if the heart is full of Tamas, or if it is wayward, no joy can be experienced... Therefore, those who aspire to attain the Holy Presence of the Lord must acquire certain habits, disciplines and qualitites. The usual, accustomed ways of life will not lead to God. They have to be modified by means of sadhana. All the sastras teach but this one lesson : keep God constantly in view and subdue the mind which makes you wander from the path.
(Prema Vahini, pg 98)