John Lightfoot on John 9:7

[ Which is by interpretation, Sent.] We have already shewn that the spring of Siloam discharged itself by a double stream into a twofold pool; the Upper pool, which was called the pool of Siloah; and the Lower, which was called the pool of Shelah; Nehemiah 3:15. Now the pool of Siloah, plainly and properly signifies Sent; but Shelah not so, as we have already noted. Probably the evangelist added this parenthesis on purpose to distinguish which of the pools the blind man was sent to wash in; viz. not in the pool Shelah, which signifies fleeces, but in the pool of Siloah, which signifies Sent.