A “skin of water” in the Bible is a container made from an animal hide, filled with water and carried on a journey. The phrase appears in Genesis 21:14, when Abraham sent Hagar away with “a skin of water” for her and her son Ishmael to drink from in the wilderness.
Where the phrase appears in Scripture
In Genesis 21:14, Abraham “got up, took bread and a skin of water, put them on Hagar’s shoulders, and sent her away with the boy.” The story continues in Genesis 21:15-16: when the water in the skin ran out, Hagar left the boy under a bush, believing he would die of thirst. In Genesis 21:19, God opened her eyes to see a well of water, and “she went and filled the skin with water and gave the boy a drink.”
What it means
In the story of Hagar and Ishmael, the empty skin marks the moment their situation became desperate, and God filling it again marks His provision for them.