The fire which exists in wood may be seen by proper means, viz., rubbing the wood. Similarly, the Soul which lives within the body may be seen by employing proper means, viz., Yoga.
अग्निर्यथा झुपायेन मथित्वा दारु दृश्यते। तथैवात्मा शरीरस्थो योगेनैवात्र दृश्यते॥