Saw and knew in the Greek text are participles dependent on the main verb said. It is more natural in English to use a finite verb for each of these participles (see most translations).

In the question Do you want to get well? there is no need to press the force of the verb want, as though to imply that the man’s own will had some force in effecting the cure. The question merely means “Would you like to get well?”

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .