Tafsir of Ash-Shu`ara' 26:155

(He said: This is a she-camel) meaning: after Allah, the Exalted, brought it forth in response to his supplication. It is narrated that they challenged him to produce a pregnant she-camel from a specific rock they pointed out, which would then give birth to a young one. Peace be upon him sat contemplating, and Gabriel, peace be upon him, said to him: "Pray two rak'ahs and ask your Lord." He did so, and the she-camel emerged, knelt down before them, and gave birth to a young one similar to itself in size. At that point, he said to them: (This is a she-camel) (that has a portion of drink) meaning: a share of water to drink, just as suqy and qit are used for a share of water or provisions. This portion of water came from a spring they possessed. In Majma' al-Bayan, it is related from Ali, may Allah, the Exalted, honor his face, that this spring was the first spring that gushed forth on earth, and Allah, the Mighty and Majestic, caused it to flow for Salih, peace be upon him. (And for you is a portion of drink on a known day) meaning: be content with your portion of water and do not crowd her while she is drinking. Ibn Abi 'Ablah recited (shurb) with a damma on the sheen in both instances.