Fat — Stupid and senseless. This making of their hearts fat, is here ascribed to the prophet, as it is ascribed to God in the repetition of this prophecy, John 12:40, because God inflicted this judgment upon them by the ministry of the prophet, partly by way of prediction, foretelling that this would be the effect of his preaching; and partly by withdrawing the light and help of his Spirit. Heavy — Make them dull of hearing. Lest — That they may not be able, as before they were not willing to see. Convert — Turn to God.
Related Commentaries of Isaiah 6:10
Isaiah 6:10
10 Make the heart of this people fat, and make their ears heavy, and shut their eyes; lest they see with their eyes, and hear with their ears, and understand with their heart, and convert, and be healed.