And it came to pass on a certain day, as he was teaching, that there were Pharisees and doctors of the law sitting by, which were come out of every town of Galilee, and Judaea, and Jerusalem: and the power of the Lord was present to heal them. On a certain day - This was when he was at Capernaum. See Mark 2:1.
The power of the Lord - Δυναμις Κυριου The mighty or miraculous power of the Lord, i.e. of Jesus, was there to heal them - as many as were diseased either in body or soul. Where the teaching of Christ is, there also is the power of Christ to redeem and save.