Dharana is the “maintaining of proper concentration”. “Proper concentration” means keeping one’s indriyas on God. In other words, this is a manifestation of a man’ aspiration towards God, towards Merging with Him.
But God in the aspect of Creator or Holy Spirit is inaccessible for direct perception at this stage of apprenticeship.
Our loving thirst for God can be partially quenched by working with an Image of a specific Divine Teacher, for example, Jesus Christ, Babaji or Sathya Sai — the One, Whose form in His past incarnation is familiar to us.
If one holds the face of a Divine Teacher in one’s anahata on the background of emotion of the most intense love that one is capable of, one gradually enters a state when it is not one who looks at the world from one’s anahata, but Him. This denotes the Yidam (this is what this Image is called) “coming alive”, or partial Merging with Him. After that one may live in Unity with Him in one’s anahata, or having moved concentration of consciousness to the chakras located in the head one can address Him in one’s anahata as an Advisor and a Teacher. And this is not an illusion, but a real Divine Teacher entering into His Image created by a spiritual devotee. He may also become an Instructor in one’s meditative trainings. He will lead His devoted and loving disciple through His Consciousness — into the Abode of the Universal Consciousness of the Creator.
“If you can visualize the Image of the Teacher in your consciousness with the most complete clarity, you can transfer your consciousness into His, and thus act, as it were, through His Power. But for this you must visualize the Image of the Teacher with utmost precision, to the minutest detail, so that the Image may not flicker, suffer distortion or change Its outlines, as frequently happens. But if following the exercise of concentration one succeeds in invoking a steady Image of the Teacher, through this one may gain the greatest benefit for oneself, for those around one, and for the work.” [2](Hierarchy:90).
“You may be asked how the entrance upon the path of Service is defined. Certainly the first sign will be renunciation of the past and total aspiring towards the future. The second sign will be realization of the Teacher within one's heart not because it is one’s “duty”, but because it is impossible otherwise. The third sign will be rejection of fear, for he who is armed by the Lord is invulnerable. The fourth will be non-condemnation, because he who strives into the future has not time to occupy himself with the refuse of yesterday. The fifth will be filling of the entire time with labor for the future. The sixth will be the joy of Service and completely offering oneself for the good of the world. The seventh will be spiritual aspiration towards the far-off worlds as a predestined path. According to these signs you will discern a spirit ready and manifested for Service. He will understand where to raise the sword for the Lord, and his word will be from within his heart.” [2] (Hierarchy:196)
Those adepts, for whom working with Yidam does not bring immediate results, may benefit from practicing visualization. They may practice creating images that help develop chakras or visualize blissful pictures of communicating with living nature etc. But only those images, which are filled with exultation of happiness, harmony, joy, subtlety and bliss will make for one’s correct spiritual development. Corresponding types of paintings, musical compositions and art photography etc. may also serve as an aid.
