Sadhana is the practice of Yoga. Tapasya is the concentration of the will to get the results of sadhana and to conquer the lower nature. Aradhana is worship of the Divine, love, self-surrender, aspiration to the Divine, calling the name, prayer. Dhyana is inner concentration of the consciousness, meditation, going inside in Samadhi. Dhyana, tapasya and aradhana are all parts of sadhana.
Strength is all right for the strong—but aspiration and the Grace answering to it are not altogether myths; they are great realities of the spiritual life.
[Sri Aurobindo: Letters on Yoga]
