Charles Ellicott Commentary Genesis 21:31

"Wherefore he called that place Beer-sheba. Because there they sware both of them." — Genesis 21:31 (ASV)

Beer-sheba. —That is, the well of seven, but with a covert allusion to the seven lambs having been used for the ratification of an oath.

Robinson found the exact site in the Wady-es-Seba, with its name still preserved as Bir-es-Seba. At this location are two wells of solid construction, the first twelve and a half feet in diameter; the other, situated about 200 yards to the south, much smaller, being only five feet in diameter. Both are lined with solid masonry, and reach down to never-failing springs in the rock. Around are stone troughs for watering the cattle, and the parapet of the larger well is worn into deep indentations by the ropes used in drawing the water (Finn, Bye-ways in Palestine, p. 190).