Mark 4:33-34

The parable-style of illustrative speaking was about the only way to get the message of the New Covenant through to the masses. The people of the day were largely uneducated (and their betters liked it that way), so just reading the Covenant like a news article would have missed the mark - and/or gotten Jesus stomped by a crowd for blasphemy. The parable delivers the message to them at an angle, so the people understand it before they realize it differs with their previous teachings.