What follows is a provisional translation (in other words, not official or authorized; see here for more) of a passage from a Tablet of ʻAbduʼl-Bahá, in which He expounds the various meanings of the terms “angels” and “jinn.” Peyman Sazedj and I worked together to produce this translation. The original text of this passage is published in Vahid Rafati, Badáyiʻ-i-Maʻání va Tafsír, pp. 252–255.
O thou who hast turned thy face towards the court of eternity, and art even as a brand afire with the flames of the Burning Bush! Concerning thy question about the term “angels” and the meaning thereof in Divine Scripture—know, verily, that by “angels,” various meanings are intended.
In relation to creation, the term “angels” applieth to those who have sanctified the hem of their garments from corrupt desires, and who mirror forth every attribute of Him Who is the Lord of the heavens. The term “angel” is a reference to their spiritual condition and a testimony to their inner being and reality. These are they whom God hath mentioned in His verses and remembered by various names. I will now recount unto thee some of these names and expound their meanings, that thou mayest understand what the Adored One hath intended through His words. Among them is “the bearers of the throne.”  Know thou that by “throne” is meant the heart of man, even as He Who is the Nightingale of Eternity and the Celestial Dove hath warbled: “The heart of the believer is the throne of the All-Merciful,”  and the Tongue of Grandeur hath, in the Hidden Words, proclaimed: “Thy heart is My home; sanctify it for My descent. Thy spirit is My place of revelation; cleanse it for My manifestation.”  For the heart is the recipient of the effulgences of divine Beauty, and the seat upon which the love of God, the Lord of the beginning and the end, hath established its sovereignty.
In relation to God, the term “angels” referreth to the Prophets of God and His Messengers, even as He hath said in the Qurʼán: “Praise be to God, Fashioner of the heavens and the earth, Who sendeth forth the angels as His Messengers with two, or three, or four pairs of wings…”  That which the All-Glorious God hath intended by “wings” in this verse are the modes of revelation and the kinds of proofs wherewith He hath sent His Messengers. These “wings” He hath made the means by which men may attain to the Wellspring of divine guidance, and all creation be led aright to the paradise of love and affection. For this, above all else, will conduce to the advancement of the world, and serve as the most potent of wings whereby the pure in heart may soar unto the Paradise of Oneness and the sacred abode of Divine Unity. Thus hath it been referred to as “wings” in the Scriptures of God.
I swear by God, O thou who hast set thy face towards Him! Were a man to incline his inner ear unto but a single verse of his Lord, and discover the delight of discerning the hidden meanings concealed therein, he would assuredly rise unto the highest peaks of righteousness, and ascend from the nether worlds of dust unto the lofty realms of truth.
In another sense, the term “angels” referreth to the pervading influence of the Will of God—as well as His perfect, all-encompassing purpose—inasmuch as it is the cause of the world’s creation, and the reason for which the frame of non-existence was arrayed with the raiment of existence. Indeed, the term “angels” may be interpreted as all the attributes of God. Were I to further elaborate on this matter, my discourse would assume an unseemly length. Whoso wisheth to fully apprise himself thereof, let him read the verses of God—the Almighty, the Beneficent—and ponder the manifold meanings revealed therein. Thereupon shall he understand the intent, and may well dispense with such things as are recorded in the books of men.
In yet another sense, the term “angels” referreth to the laws sent down from the heaven of the Will of the All-Merciful, which He hath made the supreme instrument for the protection of the world, and ordained as the source of both life and death. When these laws confer upon the believers the spirit of life, they are called “the angel of life” ; when they divest the ungodly of that same spirit, they are called “the angel of death” ; and when they protect the servants of God from misfortune, they are called “guardian angels.” In each case have they been given a specific name in the verses of God, but those who are endued with true understanding will feel neither doubtful nor perplexed by the differences among the names revealed in the Books of the Prophets.
Know, then, O thou who believest in God, that the One Who created existence from sheer nothingness, and “taught man what he knew not,”  is unconstrained to do what He willeth, and powerful to fashion a new creation as He pleaseth. No man of discernment can deny the peerless potency of His power, or gainsay the subduing force of His might. Indeed, those possessed of insight rest well assured that, if God so willeth, He would call into being creatures that are impervious to the changes and chances of this world, and inscrutable to the senses of all that dwell on earth. I will now cite for thee, in this connection, what hath been sent down from the Kingdom of God—the Mighty, the Incomparable—in response to him who had asked his Lord, the All-Glorious, about Gabriel. He saith, exalted be His grandeur and magnified be His might:
Regarding thine inquiry about the angel Gabriel, lo, He hath now arisen before Our face and proclaimeth: “O thou inquirer! Know verily that no sooner had the Tongue of Grandeur uttered His exalted words, ‘O Gabriel,’ than thou couldst behold Me outwardly manifested in the most beauteous of forms. Be not astounded thereby, for verily thy Lord is the Almighty, the Most Powerful.” 
Now concerning thy question about the “jinn”—know thou that God, exalted be He, hath created man from four elements: fire, air, water, and earth. Out of fire, heat hath been produced, and from heat, motion hath been engendered. The term “jinn” applieth when the temperament of fire in man dominateth the others, and pertaineth primarily to them that believe in God, are well assured in His signs, and strive in His path, for they were created from the fire of the divine Word which the Tongue of God hath uttered. It is for this reason that He hath said, and His Word is the Truth: “And He created the jinn from a smokeless fire.”  Thus hath He described them in His lucid Book through these weighty words: “Powerful over the disbelievers [are they that are with Muḥammad],”  for when they wage war against the perverse, thou seest them swift as brilliant lightning and subduing as a piercing spear. Exalted is He Who hath animated them with that fire kindled by the divine Lote-Tree! But when instead thou dost regard their mercy, their kindness, and their obedience to the Cause of God—as well as their sanctification from all else but Him—we refer to them as “angels,” just as we mentioned in the beginning of our explanation.
In another sense, the term “jinn” applieth to those who so excel others in their faith that thou seest them spurred into motion—a motion born of the fire which the Word of God hath ignited. For the sighs of tender affection rise from their hearts, and the flame of the love of God, the Lord of the beginning and the end, burneth brightly within their breasts.
Know thou, O inquirer, that we have expounded unto thee the true meaning of “jinn.” But know, moreover, that, in a metaphorical sense, the term “jinn” also applieth to the disbelievers, due to the pride and arrogance they demonstrate in the Cause of God, as well as the quarrels and disputes they raise with His Prophets. That which hath been sent down in the Súrih of Jinn from the Heaven of the Will of God, the Lord of the worlds, is a sufficient testimony unto the truth of both interpretations. He saith, exalted be He: “Say: It was revealed unto Me that a group of jinn gave ear [to the Qurʼán], and they said, ‘We, verily, have heard a wondrous Qurʼán; it guideth aright, therefore we believe in it and shall never ascribe any partner unto our Lord…some among us are righteous, while others are not; many and divergent are the paths we follow.’” 
 A tradition attributed to Muḥammad.
 Literally, Isráfíl, which in Islam refers to the angel who will sound a trumpet-blast on the Day of Resurrection that will cause the dead to rise from their graves.
 Literally, ʻIzráʼíl, which in Islam refers to the angel of death.
A typescript of the Arabic text of this passage appears below.