The meaning therefore is, “What I say to you in darkness,” that is, among the unbelieving Jews, “that speak ye in the light,” that is, preach it to the believing; “what ye hear in the ear,” that is, what I say unto you secretly, “that preach ye upon the housetops,” that is, openly before all men. It is a common phrase, To speak in one’s ear, that is, to speak to him privately.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).