Our Lord spat upon the ground, and made clay of the spittle, because He was the Word made flesh. The man did not see immediately as he was anointed; i. e. was, as it were, only made a catechumen. But he was sent to the pool which is called Siloam, i. e. he was baptized in Christ; and then he was enlightened. The Evangelist then explains to us the name of this pool: which is by interpretation, Sent: for, if He had not been sent, none of us would have been delivered from our sins.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Tr. xlv. 2