But some of the Pharisees said, “Why do you do what is not lawful on the Sabbath?” Luke 6:2
Lots of great discoveries are made because someone asks a simple question but sometimes the person asking the question does not really want an answer, they just want to see you squirm.
The Pharisees often tried to trap Jesus with their questions and that was their intent here; they had seen Jesus’ disciples picking and eating grain from the field. Deuteronomy 23:25 specifically permits plucking grain by hand; it was the use of harvesting tools that was prohibited.
Jesus, instead of ignoring them, asks them a question. He asks them a question about The Bible and their own history. Jesus refers to the time when a hungry David took bread from the temple (1 Samuel 21), bread that had been dedicated to God, holy bread.
I love how the living Word, the Word made flesh, uses The Bible to expose their motives and reveal the true state of their hearts to themselves, Jesus already knows what they are thinking. And that is what The Bible does, as we read it and meditate upon it we learn of a holy God, we see ourselves as we truly are; lost sinners in need of a Savior. Jesus Himself is the answer to every question of your soul, ask Him your questions.