As-Salaam alaikum,

"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, Saad.

(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 splendour 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 Jalaluddin Rumi, in his Mathnawi, Trans. by R.A Nicholson).

The universally acclaimed poet must have in mind something concerning the transcendent nature of the Letters that prefixed 29 Surahs/chapters in the Holy Qur'an, referred to as the Abbreviated Letters.
In this particular poem, we note that at the beginning of chapter 19 of the Holy Qur'an, Surah Maryam, are such Letters: Kaf, Ha, Ya, Ayn, Saad... 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); Saad- Sadiqul-Wa'd (He who keeps His promise)..