This is on account of the custom of the day, where a father and/or his household giving a blessing to a daughter when she gets married or leaves home. Here it is a blessing, which Achsah recognizes as the key to her own and probably her husband’s future. She recognizes that the desert (Negev) land she and her husband have received offers little promise. Accordingly she concretizes her need for a blessing with a request for a field with springs of water, without which she will be unable to grow the garden she needs to feed her family. Although she remains gracious and respectful, she will not be simply a passive object of men’s deals. Instead she seizes the opportunity to achieve something neither her father nor husband contemplated. But she does so without overstepping the bounds of female propriety.
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15 She said to him, “Give me a blessing. Since you have set me in the land of the Negeb, give me also springs of water.” And Caleb gave her the upper springs and the lower springs.