The human soul stands where two seas meet. ‘Abdu’l-Bahá calls it the intermediary between the Supreme Concourse and the material world, with one face turned toward the Kingdom and the other toward the earth; it is neither pure abstraction nor merely of this world, but a barzakh, an isthmus, between two realities. That position is a capacity, not a guarantee. The same reality can become luminous, merciful, and tranquil, or sink into darkness and command to evil; the zenith of virtue and the nadir of vice are both within reach of one being. It is the lowest point on the arc of descent and therefore able to rise through every grade above, but only through education; without it the soul stays where it is. The Qur’an speaks of sweet and salt waters held apart by a barrier that may not be crossed [1], an image of the seas themselves before later thinkers applied it to human nature, and the difference is worth keeping in view. From the isthmus the path runs along the arcs of ascent and descent, into the question of free will and fate, and into what distinguishes the human being from the animal.
The spirit is the power of life, the mind is the power which apprehendeth the reality of things, and the soul is an intermediary between the Supreme Concourse (or Spiritual World) and the lower concourse (or material world). It, i.e., the soul, hath two phases: The higher aspireth to the Kingdom of El-Baha, and the light of the mind shine forth from the horizon (or kingdom) unto its higher sphere; the other phase inclineth to the lower concourse of the material world and its lowest sphere is enveloped in the darkness of ignorance.
Moreover you have asked about the link [barzakh] between the material world and the spiritual world. You have stated that since there was a link between the mineral and the vegetable kingdoms and one between the vegetable and animal kingdoms, such a link may also exist between the material and the spiritual worlds after ascension. Know thou of a certainty that the soul is exalted above time and place and that the intervening link is also spiritual by nature, wholly detached from the contingent world. And upon thee be salutation and praise.
(‘Abdu’l-Bahá, to Nur Muhammad Khan (Kirman) -- AB11857)
03
Though all created things universally reflect the signs of God, it is man alone who hath been distinguished and honored with the glory of divine favors and the gift of universal bounties. He is the most great sign and the supreme exemplar; he is the perfect manifestation, the all-encompassing grace, the resplendent light, the towering mountain, the dawning-place of the Names, the dayspring of the most exalted attributes, the all-embracing isthmus, the shining horizon, the meeting place of the two seas, the confluence of the two rivers, and while being the center from which the lights of reality shine forth, he is also the mine of dark evil.
O thou who art enkindled with the fire of the love of God!
In the world of existence there are higher and lower stations, and the ranks of the highest heaven and the depths of hell are visible, and the zenith of virtues and the nadir of vices are proven and known. And human reality is the connecting isthmus [barzakh] and dividing line, meaning it possesses the capacity both to ascend to the highest stations and to fall to the lowest depths of destruction.
The available source contains an omission or incomplete wording; sentence boundaries need review.
05
On the other hand, we find in him justice, sincerity, faithfulness, knowledge, wisdom, illumination, mercy and pity, coupled with intellect, comprehension, the power to grasp the realities of things and the ability to penetrate the truths of existence. All these great perfections are to be found in man. Therefore, we say that man is a reality which stands between light and darkness. From this standpoint his nature is threefold: animal, human and divine. The animal nature is darkness; the heavenly is light in light.
(‘Abdu’l-Bahá, Public address given at Theosophical Society on 1912-Dec-04 -- ABU0033)
06
And what is meant by the form is the form of humanity, and it is the form which the Merciful fashioned with His hand and placed within it the forms of the worlds, and it is the meeting place of the two seas and the isthmus of the two genesis. God inscribed within it the decrees of the worlds, and the indication of fashioning is its non-dissolution for accepting the manifestation.
(The Báb, Tafsir-i-Suratu'l-Baqarah (Commentary on the Surah of the Cow I) -- BB00008)
07
The human spirit (ruh-i insani), in other words the rational soul (nafs-i natiqa), in the world of existence is the intermediary between things corporeal ('disengaged' mujarradat) and delimited worldly things (mutahayyizat); that is to say, between realities spiritual and things corporeal. From one vantage point it possesses spiritual refinement while from the other it exhibits the crassness of carnality, animalistic traits and worldly characteristics. It is neither an absolute abstraction nor is it completely of the world but is the confluence of two seas (majma' al-bahrayn) and a barzakh ("barrier", "isthmus") between two realities (amrayn).
(‘Abdu’l-Bahá, 1911-Jun-01, to Abbas Qabil -- AB02513)
08
For the inner reality of man is a demarcation line between the shadow and the light, a place where the two seas meet; it is the lowest point on the arc of descent, and therefore is it capable of gaining all the grades above. With education it can achieve all excellence; devoid of education it will stay on, at the lowest point of imperfection.
(‘Abdu’l-Bahá, to Teachers of Tarbiyat School -- AB01170)
Further quotations · supplied wording and references
09
How often has that same locus of the Universal Will (mazhar-i-mashiyyat-i-kulliya) opened up a gate of mystic knowledge (ma'rifa) in the barzakh.
(The Bab, provisional translation, Persian Bayan 2:9, p. 44, in MacEoin, Rituals, p. 76, fn. 77)
It is He Who has let free the two bodies of flowing water: one palpable and sweet, and the other salt and bitter; yet has He made a barrier (barzakh) between them, a partition that is forbidden to be passed.
Qur'an 25:53; see also 55:19-21, 23:100, 35:12
Supplied quotation · catalogue passage not verified