There are a few passages in The Hidden Words which refer implicitly to the Covenant of Bahá'u'lláh -- a Covenant which later became explicit with the revelation of the Will and Testament of Bahá'u'lláh, designated by Him the Kitáb-i-'Ahdi (The Book of My Covenant).
'Abdu'l-Bahá, Who is the Centre of that same Covenant and the appointed Interpreter of the words of Bahá'u'lláh, has explained the meaning of some of these passages. One instance is the following:
O My Friends!
Have ye forgotten that true and radiant morn, when in those hallowed and blessed surroundings ye were all gathered in My presence beneath the shade of the tree of life, which is planted in the all-glorious paradise? Awestruck ye listened as I gave utterance to these three most holy words: O friends! Prefer not your will to Mine, never desire that which I have not desired for you, and approach Me not with lifeless hearts, defiled with worldly desires and cravings. Would ye but sanctify your souls, ye would at this present hour recall that place and those surroundings, and the truth of My utterance should be made evident unto all of you.(Baha’u’llah, Persian Hidden Words, no. 19)
The 'true and radiant morn', 'Abdu'l-Bahá stated, refers to the Revelation of the Báb, the 'tree of life' to Bahá'u'lláh, and the 'hallowed and blessed surroundings' to the heart of the individual. He further explained that the gathering referred to in this verse was not a physical but a spiritual one. The call of God was raised within the sanctuary of their hearts; but they did not respond and were bewildered and awestruck.
In other Tablets, 'Abdu'l-Bahá interpreted the meaning of the gathering beneath the shade of the 'tree of life' as the establishment of the Covenant of Bahá'u'lláh. 'The Lord, the All-Glorified,' in the words of 'Abdu'l-Bahá, 'hath, beneath the shade of the Tree of Anisa [tree of life], made a new Covenant and established a great Testament...'(Shoghi Effendi, ‘God Passes By’) That this Covenant was established at so early a stage in the ministry of Bahá'u'lláh is one of the mysteries of Divine Revelation. Indeed, in a Tablet 'Abdu'l-Bahá stated that when the day-star of the Revelation of Bahá'u'lláh dawned upon humanity, the first ray which shed its light upon those gathered beneath the 'tree of life' was that of the Covenant of Bahá'u'lláh.
Another passage in The Hidden Words which refers to this Covenant is the following:
O My Friends!
Call ye to mind that covenant ye have entered into with Me upon Mount Paran, situate within the hallowed precincts of Zaman. I have taken to witness the concourse on high and the dwellers in the city of eternity, yet now none do I find faithful unto the covenant. Of a certainty pride and rebellion have effaced it from the hearts, in such wise that no trace thereof remaineth. Yet knowing this, I waited and disclosed it not. (Baha’u’llah, Persian Hidden Words, no. 71)
'Abdu'l-Bahá has stated that the covenant upon Mount Paran refers to the Covenant of Bahá'u'lláh which was written by the Exalted Pen in the Holy Land and which was announced there after His ascension. Finally, the 'wings' and the 'comb' mentioned in the following verse are both interpreted by 'Abdu'l-Bahá as the Covenant of Bahá'u'lláh:
O Son of Desire!
How long wilt thou soar in the realms of desire? Wings have I bestowed upon thee, that thou mayest fly to the realms of mystic holiness and not the regions of satanic fancy. The comb, too, have I given thee that thou mayest dress My raven locks, and not lacerate My throat. (Baha’u’llah, Persian Hidden Words, no. 79) (Adib Taherzadeh, The Revelation of Baha'u'llah v 1, pp. 80-81)