The Pharisees are not asking for another sign or a miracle like a healing, but specifically a sign from heaven, something like what happened to Joshua when the sun stood still in heaven (Joshua 10:12–14) or to Elijah who called down fire from heaven (2 Kings 1:10, 2 Kings 1:12). Signs are a prominent feature in the story of Moses (Exodus 4:1–9, Exodus 4:29–31; Exodus 7:8–22, etc.), and are intended to be accepted as proof of his divine mission.
11 The Pharisees came and began to argue with him, seeking from him a sign from heaven to test him.