SB 3.28.18

kīrtanya-tīrtha-yaśasaṁ
 puṇya-śloka-yaśaskaram
dhyāyed devaṁ samagrāṅgaṁ
 yāvan na cyavate manaḥ
Word for word: 
kīrtanya — worth singing; tīrtha-yaśasam — the glories of the Lord; puṇya-śloka — of the devotees; yaśaḥ-karam — enhancing the glory; dhyāyet — one should meditate; devam — upon the Lord; samagra-aṅgam — all the limbs; yāvat — as much as; na — not; cyavate — deviates; manaḥ — the mind.
Translation: 
The glory of the Lord is always worth singing, for His glories enhance the glories of His devotees. One should therefore meditate upon the Supreme Personality of Godhead and upon His devotees. One should meditate on the eternal form of the Lord until the mind becomes fixed.
Purport: 

One has to fix his mind on the Supreme Personality of Godhead constantly. When one is accustomed to thinking of one of the innumerable forms of the Lord — Kṛṣṇa, Viṣṇu, Rāma, Nārāyaṇa, etc. — he has reached the perfection of yoga. This is confirmed in the Brahma-saṁhitā: a person who has developed pure love for the Lord, and whose eyes are smeared with the ointment of transcendental loving exchange, always sees within his heart the Supreme Personality of Godhead. The devotees especially see the Lord in the beautiful blackish form of Śyāmasundara. That is the perfection of yoga. This yoga system should be continued until the mind does not vacillate for a moment. Oṁ tad viṣṇoḥ paramaṁ padaṁ sadā paśyanti sūrayaḥ: the form of Viṣṇu is the highest individuality and is always visible to sages and saintly persons.

The same purpose is served when a devotee worships the form of the Lord in the temple. There is no difference between devotional service in the temple and meditation on the form of the Lord, since the form of the Lord is the same whether He appears within the mind or in some concrete element. There are eight kinds of forms recommended for the devotees to see. The forms may be made out of sand, clay, wood or stone, they may be contemplated within the mind or made of jewels, metal or painted colors, but all the forms are of the same value. It is not that one who meditates on the form within the mind sees differently from one who worships the form in the temple. The Supreme Personality of Godhead is absolute, and there is therefore no difference between the two. The impersonalists, who desire to disregard the eternal form of the Lord, imagine some round figure. They especially prefer the oṁkāra, which also has form. In Bhagavad-gītā it is stated that oṁkāra is the letter form of the Lord. Similarly, there are statue forms and painting forms of the Lord.

Another significant word in this verse is puṇya-śloka-yaśaskaram. The devotee is called puṇya-śloka. As one becomes purified by chanting the holy name of the Lord, so one can become purified simply by chanting the name of a holy devotee. The pure devotee of the Lord and the Lord Himself are nondifferent. It is sometimes feasible to chant the name of a holy devotee. This is a very sanctified process. Lord Caitanya was once chanting the holy names of the gopīs when His students criticized Him: “Why are You chanting the names of the gopīs? Why not ‘Kṛṣṇa’?” Lord Caitanya was irritated by the criticism, and so there was some misunderstanding between Him and His students. He wanted to chastise them for desiring to instruct Him on the transcendental process of chanting.

The beauty of the Lord is that the devotees who are connected with His activities are also glorified. Arjuna, Prahlāda, Janaka Mahārāja, Bali Mahārāja and many other devotees were not even in the renounced order of life, but were householders. Some of them, such as Prahlāda Mahārāja and Bali Mahārāja, were born of demoniac families. Prahlāda Mahārāja’s father was a demon, and Bali Mahārāja was the grandson of Prahlāda Mahārāja, but still they have become famous because of their association with the Lord. Anyone who is eternally associated with the Lord is glorified with the Lord. The conclusion is that a perfect yogī should always be accustomed to seeing the form of the Lord, and unless the mind is fixed in that way, he should continue practicing yoga.