Why did Jesus perform miracles, preach, and teach?
Jesus performed miracles, preached, and taught to prove to the Jewish people of His day that He was the promised Messiah. This was the whole scope of His earthly ministry, confirming that He was the fulfillment of Old Testament promises.
Les explains that the reason for all of Jesus' miracles, the reason for all of His preaching and teaching, was to prove to the Jew of His day that He was the promised Messiah. He stresses that this is the whole scope of Christ's ministry. The context further shows that Jesus came out of the Old Testament promises, and Israel was awaiting the King, the Anointed One, or Messiah, which in Greek is the Christ. Thus His works and words served to authenticate His identity as that promised Messiah.