The Collaborative International Dictionary of English v.0.48:

Preach \Preach\, v. i. [imp. & p. p. Preached; p. pr. & vb. n.
   Preaching.] [OE. prechen, OF. preechier, F. pr[^e]cher, fr.
   L. praedicare to cry in public, to proclaim; prae before +
   dicare to make known, dicere to say; or perhaps from
   (assumed) LL. praedictare. See Diction, and cf.
   Predicate, Predict.]
   1. To proclaim or publish tidings; specifically, to proclaim
      the gospel; to discourse publicly on a religious subject,
      or from a text of Scripture; to deliver a sermon.
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            How shall they preach, except they be sent? --Rom.
                                                  x. 15.
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            From that time Jesus began to preach. --Matt. iv.
                                                  17.
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   2. To give serious advice on morals or religion; to discourse
      in the manner of a preacher.
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