Acts 20:21

Repentance toward God, and faith toward our Lord Jesus Christ. — These, under all varieties of form, whether speaking to Jews or Gentiles, to philosophers at Athens (Acts 17:30) or peasants of Lystra (Acts 14:15), formed the substance of his teaching. It is obvious, however, that out of these might be developed a whole system of theology — why repentance was needed, and what it was, and how it should show itself, what was involved in the statement that Jesus was the Christ, and why men should believe in Him, and what works were the proper fruit of faith. All these were questions which had to be answered, before even the most elementary truths could be rightly apprehended.