It is related in the fourth chapter of Matthew that Jesus " began to preach " by saying, " Repent: for the kingdom of heaven is at hand."
It is also related that he did this preaching in fulfilment of the prophecy of Esaias, who forsaw that " the people which sat in darkness saw a great light; and to them which sat in the region and shadow of death light is sprung up."
What gladder tidings could they receive who are sitting in darkness, than that a great Light was about to dawn?