Tafsir of Al-Mulk 67:30

"Say, have you considered" means: tell me.

"If your water were to become sunken" means: vanished and gone entirely into the earth. According to al-Kalbi, it means that buckets cannot reach it. It is an infinitive used as a description for the sake of hyperbole, or it is interpreted as an active participle. Regardless, the intended meaning is not a specific water source, even though the verse, as narrated by Ibn al-Mundhir and al-Fakihi from Ibn al-Kalbi, was revealed regarding the Well of Zamzam and the well of Maymun ibn al-Hadrami.

"Then who could bring you flowing water?" This means running water, or water that is visible and easy to obtain, accessible to the hands. It is in the form of fa'il (active participle) derived from ma'ana, or maf'ul (passive participle) derived from 'aynun. This is a warning specifically regarding worldly life, following the previous warning to alert one to the greater matter by means of the lesser: if you will not worship Him, the Almighty and Majestic, for the sake of the everlasting life, then worship Him for the sake of this fleeting one.

Some of the scoffers recited this verse; when they heard "Then who could bring you flowing water?", one said, "Pickaxes and shovels will bring it," whereupon the water of his own eyes vanished. We seek refuge in Allah Almighty from audacity against Allah, the Majestic, and His signs. Interpreting the verses in this manner is what some Imams have chosen, and it is deeper in significance than others. Allah, the Almighty, knows best the secrets of His speech.