You don't require any artificial method to think of God. It is natural. If you simply come to the temple daily, chant in the front of the Deity:
- Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare
- Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare
then you become advanced immediately. Sa vai manaḥ kṛṣṇa-padāravindayor vacāṁsi vaikuṇṭha-guṇānuvarṇane (SB 9.4.18). Now there are books. Either you chant, sit down in the Deity room in front of the Deity, see how āratrika is going on, how Deity is nicely dressed with flower, ornaments, so if you constantly be engaged in thinking of the Deity, that is first-class meditation, not artificially going to . . . that is not possible at the present moment, that, as it is recommended in the Bhagavad-gītā, you have to select a very solitary place and you have to sit down under certain posture, looking half-opened eyes on the tip of the nose so that you may not sleep in the name of meditation. There are so many. And you have to follow brahmacārya. All these rules and regulations are there: dhyāna, dhāraṅā, āsana, prāṇāyāma. Prāṇāyāma . . . then? What is called? Pratyāhāra. Pratyāhāra means you have to completely withdraw the senses from sense gratification. That is called pratyāhāra. Then there is samādhi.
So this yoga system is recommended, but it is very, very difficult. Five thousand years ago, when Kṛṣṇa explained this haṭha-yoga system in the Sixth Chapter to Arjuna . . . Arjuna was honest man. He flatly denied, "Kṛṣṇa, these things cannot be done by me." Because in those days, especially a person like Arjuna, why he should speak lies? This meditation is not possible. It was only possible in the Satya-yuga, when people were very peaceful, long duration of life, there was no artificial necessities of life. Kṛte yad dhyāyato viṣṇum. At that time, to meditate upon Viṣṇu, and for years . . . just like Vālmīki Muni. He practiced meditation for sixty thousands of years, then he got perfection. At that time people used to live for 100,000.
So this meditation is very difficult to execute at the present moment. That is the verdict of the Vedic literature.
- kṛte yad dhyāyato viṣṇuṁ
- tretāyāṁ yajato makhaiḥ
- dvāpare paricaryāyaṁ
- kalau tad dhari-kīrtanāt
- (SB 12.3.52)
The meditation which was possible in the kṛte, in the Satya-yuga . . . satya-yuga continued for twelve lakhs of years; then Treta-yuga, eight lakhs of years . . . no, Satya-yuga, eighteen lakhs; then Treta-yuga, twelve lakhs; then Dvāpara-yuga, eight lakhs; and Kali-yuga, four lakhs. Altogether forty-three. So bhakti-yoga includes everything. So this process, this arcanā process. If we . . . everyone, alternately, they should learn how to worship. That will give the impression of the Lord within the heart, and then, either you are walking or you are sitting or you are lying or you are eating or you are talking, you'll always think of Kṛṣṇa. This is the process. It will be automatically done. Sthitaṁ vrajantam āsīnaṁ śayānaṁ vā guhāśayam. Generally the yogīs, they try to find out the Viṣṇu mūrti within the core of the heart, but this is as good. When you are walking on the street, then, if you are thinking, there will be no, I mean to say, hindrance to your activities, but you can think of Kṛṣṇa. Sa vai manaḥ kṛṣṇaḥ. Just like Mahārāja Ambarish. He was emperor. He had many responsibilities, but he practiced how to think of Kṛṣṇa always.