The Nature of Meditation:
Baha’u’llah says there is a sign (from God) in every phenomenon: the sign of the intellect is contemplation and the sign of contemplation is silence, because it is impossible for a man to do two things at one time – he cannot both speak and meditate.
It is an axiomatic fact that while you meditate you are speaking with your own spirit. In that state of mind you put certain questions to your spirit and the spirit answers: the light breaks forth and the reality is revealed.
You cannot apply the name `man’ to any being void of this faculty of meditation; without it he would be a mere animal, lower than the beasts.
Through the faculty of meditation man attains to eternal life; through it he receives the breath of the Holy Spirit – the bestowal of the Spirit is given in reflection and meditation.
The spirit of man is itself informed and strengthened during meditation; through it affairs of which man knew nothing are unfolded before his view. Through it he receives Divine inspiration, through it he receives heavenly food.
Meditation is the key for opening the doors of mysteries. In that state man abstracts himself: in that state man withdraws himself from all outside objects; in that subjective mood he is immersed in the ocean of spiritual life and can unfold the secrets of things-in-themselves. To illustrate this, think of man as endowed with two kinds of sight; when the power of insight is being used the outward power of vision does not see.
This faculty of meditation frees man from the animal nature, discerns the reality of things, puts man in touch with God.
This faculty brings forth from the invisible plane the sciences and arts. Through the meditative faculty inventions are made possible, colossal undertakings are carried out; through it governments can run smoothly. Through this faculty man enters into the very Kingdom of God.
Nevertheless some thoughts are useless to man; they are like waves moving in the sea without result. But if the faculty of meditation is bathed in the inner light and characterized with divine attributes, the results will be confirmed.
The meditative faculty is akin to the mirror; if you put it before earthly objects it will reflect them. Therefore if the spirit of man is contemplating earthly subjects he will be informed of these.
But if you turn the mirror of your spirits heavenwards, the heavenly constellations and the rays of the Sun of Reality will be reflected in your hearts, and the virtues of the Kingdom will be obtained.
Therefore let us keep this faculty rightly directed – turning it to the heavenly Sun and not to earthly objects – so that we may discover the secrets of the Kingdom, and comprehend the allegories of the Bible and the mysteries of the spirit.
May we indeed become mirrors reflecting the heavenly realities, and may we become so pure as to reflect the stars of heaven.
(`Abdu’l-Baha: Paris Talks, pp. 174-176)

The inspiration received through meditation is of a nature that one cannot measure or determine. God can inspire into our minds things that we had no previous knowledge of, if He desires to do so.
(Shoghi Effendi: Prayer, Meditation, …, p. 241)

Purpose:
The source of crafts, sciences and arts is the power of reflection. Make ye every effort that out of this ideal mine there may gleam forth such pearls of wisdom and utterance as will promote the well-being and harmony of all the kindreds of the earth.
(Baha’u’llah: Tablets of Baha’u’llah, p. 72)

For the core of religious faith is that mystic feeling which unites Man with God. This state of spiritual communion can be brought about and maintained by means of meditation and prayer.
(Shoghi Effendi: Directives of the Guardian, p. 86)

Through meditation doors of deeper knowledge and inspiration may be opened.
(Shoghi Effendi: Directives of the Guardian, p. 47)

Prayer and meditation are very important factors in deepening the spiritual life of the individual, but with them must go also action and example, as these are the tangible results of the former. Both are essential.
(Shoghi Effendi: Prayer, Meditation, …, p. 241)

It is not sufficient to pray diligently for guidance, but this prayer must be followed by meditation as to the best methods of action and then action itself.
(Shoghi Effendi: Guidelines for Teaching, p. 325)

When a person becomes a Baha’i, actually what takes place is that the seed of the spirit starts to grow in the human soul. This seed must be watered by the outpourings of the Holy Spirit. These gifts of the spirit are received through prayer, meditation, study of the Holy Utterances and service to the Cause of God….
(Shoghi Effendi: The Importance of Deepening, pp. 231-232)

Subjects for Meditation:
Immerse yourselves in the ocean of My words, that ye may unravel its secrets, and discover all the pearls of wisdom that lie hid in its depths.
(Baha’u’llah: Gleanings, p. 136)

Meditate diligently upon the Cause of thy Lord. Strive to know Him through His own Self and not through others. For no one else besides Him can ever profit thee.
(Baha’u’llah: Gleanings, p. 148)

Were any man to ponder in his heart that which the Pen of the Most High hath revealed and to taste of its sweetness, he would, of a certainty, find himself emptied and delivered from his own desires, and utterly subservient to the Will of the Almighty. Happy is the man that hath attained so high a station, and hath not deprived himself of so bountiful a grace.
(Baha’u’llah: Gleanings, p. 343)

Do thou meditate on that which We have revealed unto thee, that thou mayest discover the purpose of God, thy Lord, and the Lord of all worlds. In these words the mysteries of Divine Wisdom have been treasured.
(Baha’u’llah: Gleanings, p. 153)

Ponder in thine heart the revelation of the Soul of God that pervadeth all His Laws, and contrast it with that base and appetitive nature that hath rebelled against Him, that forbiddeth men to turn unto the Lord of Names, and impelleth them to walk after their lusts and wickedness.
(Baha’u’llah: Gleanings, pp. 160-161)

Guidelines for Meditation:
The first thing to do is to acquire a thirst for Spirituality, then Live the Life! Live the Life! Live the Life! The way to acquire this thirst is to meditate upon the future life. Study the Holy Words, read your Bible, read the Holy Books, especially study the Holy Utterances of Baha’u’llah; Prayer and Meditation, take much time for these two.
(`Abdu’l-Baha: The Importance of Deepening, p. 204)

There are no set forms of meditation prescribed in the teachings, no plan, as such, for inner development. The friends are urged – nay enjoined – to pray, and they also should meditate, but the manner of doing the latter is left entirely to the individual.
(Shoghi Effendi: Prayer, Meditation, …, p. 240)

He [Shoghi Effendi] thinks it would be wiser for the Baha’is to use the Meditations given by Baha’u’llah, and not any set form of meditation recommended by someone else; but the believers must be left free in these details and allowed to have personal latitude in finding their own level of communion with God.
(Shoghi Effendi: Prayer, Meditation, …, p. 243)

Shoghi Effendi indicates that the fasting period, which involves complete abstention from food and drink from sunrise till sunset, is
” …essentially a period of meditation and prayer, of
spiritual recuperation, during which the believer must
strive to make the necessary readjustments in his inner
life, and to refresh and reinvigorate the spiritual forces
latent in his soul.”

(The Universal House of Justice: Aqdas: Notes, pp. 176-177)