a ewe lamb: a young female sheep, as distinct from a male lamb or a full-grown ewe
Hebrew names the animals of a flock closely, because an animal's sex and age decided what it was for and what it was worth. This word picks out one of those slots: a sheep, young, and female. She is not yet the grown mother of the flock (רָחֵל), and she is not the male lamb (כֶּבֶשׂ) that carries most of Israel's offering laws. For a family living off its flock she was the most promising animal in the pen, since she would go on to bear young and give milk.
She appears in only nine verses, and they fall into three settings.
- Abraham sets seven of them apart at Beersheba, and Abimelech accepts them as the standing proof that Abraham dug the well there.
- The offering laws call for one wherever the ritual requires a female animal, at the cleansing of a person healed of a skin disease and at the close of a Nazirite's vow.
- Nathan gives one to the poor man in the story he tells David, the single animal that man owned and raised beside his own children.
Being female is doing real work in each of those settings. Seven breeding animals were an expensive thing to hand over, which is what made them a convincing witness to an oath. A law that asks for a female is asking for a particular animal, not just any lamb. And in the story Nathan tells, the poor man's lamb is a she, carried in his arms like a daughter, which is what lets the picture stand for a man's wife without the prophet ever having to say so.
Hebrew writes this word two ways, swapping its last two letters (כִּשְׂבָּה in Leviticus 5:6). The two spellings are one word with one meaning, the same swap the language makes with the word for a male lamb.