Charles Ellicott Commentary Mark 5:30

"And straightway Jesus, perceiving in himself that the power [proceeding] from him had gone forth, turned him about in the crowd, and said, Who touched my garments?" — Mark 5:30 (ASV)

That virtue had gone out of him—Literally, knowing fully in Himself the virtue that had gone out of Him. The word “virtue” is used in the old medical sense, the power or force which brings about a certain definite result. So men spoke of the soporific “virtue” of this or that drug. And the term is used here, not less than in Luke 5:17, with a like technical precision, for the supernatural power that, as it were, flowed out at the touch of faith.