The process of meditation should begin from the lotus feet of the Lord and progress to His smiling face. The meditation should be concentrated upon the lotus feet, then the calves, then the thighs, and in this way higher and higher. The more the mind becomes fixed upon the different parts of the limbs, one after another, the more the intelligence becomes purified. (SB 2.2.13)
…The process of meditation recommended in the Śrīmad-Bhāgavatam is not to fix one’s attention on something impersonal or void. The meditation should concentrate on the person of the Supreme Godhead, either in His virāṭ-rūpa, the gigantic universal form, or in His sac-cid-ānanda-vigraha [Bs. 5.1], as described in the scriptures. There are authorized descriptions of Viṣṇu forms, and there are authorized representations of Deities in the temples. Thus one can practice meditating upon the Deity, concentrating his mind on the lotus feet of the Lord and gradually rising higher and higher, up to His smiling face.
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The Hare Krishna Movement 