Matthew 4:23-25, 23 And Jesus went about all Galilee, teaching in their synagogues, preaching the gospel of the kingdom, and healing all kinds of sickness and all kinds of disease among the people. 24 Then His fame went throughout all Syria; and they brought to Him all sick people who were afflicted with various diseases and torments, and those who were demon-possessed, epileptics, and paralytics; and He healed them. 25 Great multitudes followed Him—from Galilee, and from Decapolis, Jerusalem, Judea, and beyond the Jordan. (NKJV)
From the above scripture we see 4 facets of the ministry of Jesus, 1) Preaching, 2) Teaching, 3) Healing, 4) Casting out demons. In Mark 1:27, those who witnessed Jesus casting out a demon questioned saying “what is in His voice?” They recognised that Jesus had power in His voice and that the demons recognised his authority in His voice. We need to be a voice, not an echo!