"He (God), for the sake of His
Servants, became (symbolized by) the letter Kaf of KAFI (All-Sufficing), (in token of) the truth of the promise of
Kaf, Ha, Ya, Ayn, Sad.
(God saith), 'I am All-Sufficing :
I will give thee all good, without
(the intervention of) a secondary cause, without the mediation of another' s aid.
I am All-Sufficing : I will give thee satiety without bread, I will give thee sovereignty without soldiers and armies..
I will give thee instruction without a book and teacher.
I am All-Sufficing : I will make the grave and the pit a (spacious) playing - field.
To a Moses I give heart (courage) with a single rod, that he may brandish swords against a multitude.
(Such) a light and splendor do I give to the hand of Moses that it is slapping the sun (in triumph).
I make the wooden staff a seven-headed dragon, which the female dragon does not (conceive and) bring to birth from the male.
After : Maulana Jalaluddin Rumi, in his Mathnawi, Trans. by Prof. R. A Nicholson.

The poet must have in mind something concerning the transcendent nature of the Letters that prefixed 29 Surahs/Chapters of the Holy Qur'an, referred to as the Abbreviated Letters.
In this case forming the subject of the poem above, at the beginning of chapter 19 (Maryam) of the Holy Qur'an are such letters :-- Kaf, Ha, Ya, Ain, Sad... Which some Ulama interpret as :Kaf--The Divine Name Kafi (All-Sufficing), Ha, - The Divine Name Hadi (He who guides the Faithful), Ya- Yad (the Hand which bestows rizq on all), Ayn- The Divine Name Alim (Omniscient), Sad- Sadiqul- Wa'd (He who keeps His promise)...