Luke 8:45

And Jesus said, Who is it that toucheth me? And when all denied, Peter said, and they that were with him, Master, the multitude press thee and crush thee. But Jesus said, Some one did touch me; for I perceived that power had gone forth from me.

Who touched me ...? Here, to be sure, are the grounds of cavil. Did not Christ know all things? Why the perplexity here? Of course, there was no perplexity. Mark said, "He looked round to see her that had done this thing" (Mark 5:32); and it is certain that Jesus knew, not merely that some woman had touched him, but which woman had done so, as well. As Trench observed:

Elisha said, "Whence cometh thou, Gehazi?" (2 Kings 5:25); and God said, "Adam, where art thou?" (Genesis 3:9); and to Cain, "Where is Abel thy brother?" (Genesis 4:9); and, in every case there is a moral purpose in the question.[23]

So, there was a moral purpose of the question here. Jesus would not permit this woman of such commendable faith to receive in secrecy, and by stealth, in a sense, the blessing which he willed that she should receive. Moreover, following her confession, he would extend the blessing to include salvation itself. Also, there would be the tangential benefit of giving the wonder the kind of publicity and publication which so great a cure deserved.