John Gill

Seeing many things, but thou observest not,.... The Scribes and Pharisees, saw Christ in the flesh; they saw the miracles he did; they saw the blind receive their sight, the lame walk, the lepers cleansed, the deaf hear, and the dead raised; yet they did not give note to these things, and keep them in their minds, and regard them as clear proofs of his being the Messiah: opening the ears, but he heareth not; they heard John Baptist preach, the forerunner of Christ, and the testimony he bore of him; they heard Christ himself and his apostles; they sometimes opened their ears, and seemed to listen and hear with attention, and wonder at what they heard; and some would own, that never man spake like Jesus; and yet understood not his speech, and hardened their hearts against him; they saw many things with their bodily eyes, but perceived them not with the eyes of their understandings; they heard with their ears, but understood not in their hearts; for their eyes were shut and their ears heavy, Isa 6:9.