Matthew 10:27

What I tell you in darkness] A prophecy that the labours of the apostles will be more successful than those of Jesus Himself. He taught with indifferent success in the obscurity of an insignificant and remote province. They will teach successfully in the publicity of the great cities of the empire, Antioch, Ephesus, Corinth, Alexandria, Rome. What ye hear in the ear] In the Jewish schools the rabbi sat in his chair, and whispered in Hebrew into the ear of his interpreter, who then proclaimed aloud in the vulgar tongue what the rabbi had said. So the apostles were to proclaim to the wide world what Christ had whispered to them in the retirement of Galilee. Upon the housetops] Proclamations are still made in the East from the flat roofs of houses. E.g. the sabbath is proclaimed by the 'attendant' of the synagogue, who ascends to a lofty housetop, and blows there three times with the synagogue-trumpet.