Devibhagavatapurana 7.34.41

7.34.41

yogavṛtteḥ purā svasminbhāvayedakṣaratrayam |
devīpraṇavasaṃjñasya dhyānārthaṃ mantravācyayoḥ ||

When by the constant practice, as mentioned above, one's heart is fit for Samâdhi (being absorbed in the Spirit), just before that, he should understand the meanings of the separate letters in the seed Mantra of Mahâmâyâ. The letter "Ha" means gross body and the letter "Ra" means subtle body and the letter "Î" means the causal body; the (dot over the semicircle) is the fourth "Turîya" state of Mine. Thus meditating on the separate differentiated states, the intelligent man should meditate on the aforesaid three Vîjas in the Cosmic body also and he should then try to establish the identity between the two. Before enteriing into Samâdhi, after very carefully thinking the above, one should close one's eyes and meditate on Me, the Supreme Deity of the Universe, the Luminous and Self-Ellulgent Brahmâ.