This verb means 'to dig deep' or 'deepen,' describing the action of excavating to create depth. Jesus uses it in His parable of the two builders (Luke 6:48): the wise builder 'dug deep' (ἐβάθυνεν) and laid a foundation on rock, so when the flood came, the house stood firm. The term emphasizes the labor and foresight required to build on a solid base—it's not enough to build on the surface; one must dig down to bedrock. Classical usage includes deepening battle formations and hollowing out channels. Jesus' metaphor is transparent: hearing and obeying His words requires deep, costly commitment, not superficial assent.