"Ichcha-Shakti (the Will Power) arises from thoughts. This 'Iccha-Shakti' is the source of several other potencies like intellectual power, the discriminating capacity and others. To develop this 'Ichcha-Shakti' (Will Power), one has to worship Devi. This calls for the cultivation of renunciation or detachment. For instance, if one has a desire for various drinks, he can bring the desire under control by giving up, to begin with, the desire for some of them. Thereby the Will Power (Ichcha-Shakti) is developed, and in due course, it becomes easier to give up other desires. In Vedantic parlance, this is described as 'Vairaagya' (renouncing all attachments). Vairaagya is not abandonment of hearth and home and retiring to a forest. It means developing godly thoughts and reducing worldly feelings. It is when this balanced development takes place that one acquire-control over the powers of nature (Praakrita Shakti). When these powers are got, the mental power in a person increases."
Sai Baba, SS, 12/92, pp. 304 & 305