"1. The binding of the perceiving consciousness to a certain region is attention (dharana). Emerson quotes Sir Isaac Newton as saying that he made his great discoveries by intending his mind on them. That is what is meant here.... It is the power to focus the consciousness on a given spot, and hold it there Attention is the first and indispensable step in all knowledge. Attention to spiritual things is the first step to spiritual knowledge."
January 1, 1970
https://en.wikiquote.org/wiki/Yoga_Sutras_of_Patanjali