What does John 5:12 mean?

Jesus frequently clashed with Jerusalem's local religious leaders. The root cause of that conflict was their rejection of God, in favor of their own traditions (Matthew 15:3–9). One particularly sensitive tradition involved the Sabbath day. The law of Moses forbade doing work on the Sabbath. The Pharisees had added layers of traditions, in the form of extra rules and regulations, which they saw as equally binding. Carrying a load—any load—counted as "work," in their eyes.

After Jesus heals a man who had been crippled for thirty-eight years, he instructed him to take his bed and walk. This draws the attention of the Pharisees. Of course, they have every right to investigate. Upholding the Law, and the truth, is what they are supposed to be doing. However, it quickly becomes clear that their traditions are far more important, to them, than their actual spiritual obligations.

In particular, verses 11 and 12 show the vivid problem with their perspective. The man who had been healed was crippled for nearly forty years. More than likely, everyone in this area had seen him before and knew about his condition. Yet, here he is, walking! Even if the Pharisees knew nothing of the man, he tells them specifically that he has been healed and that the man who healed him told him to walk with his bed.

Rather than asking, "who healed you?" or even "how were you healed?" these religious leaders ask a question which reveals the hardness of their own hearts: "who told you to take up your bed and walk?" In their minds, this really means, "who told you to violate our tradition?" Rather than being amazed or curious about the miracle, all they see is someone breaking their customs (John 5:16).