When the Pharisees heard that Yeshua was casting out demons, the claimed He was doing this by the power of Beelzebub. Now the Pharisees want a sign “from heaven.” They wrongly reasoned that some miracles here on earth could come from Beelzebub. They thought that if they saw a sign from heaven, then they could determine if Yeshua is really a prophet from Elohim or not. Yeshua showed signs before, why would He not show a sign for the Pharisees? Yeshua did not want them to heed His warnings. He already said they were not to understand His message and that is why He spoke in parables (Matt. 13:9-15).
Yeshua does not want everyone to understand what He is saying. He has good reason for this. It is a fulfillment of prophecy. In the Psalms we are told that Elohim will speak in parables for His people to know His Torah (Psalm 78:1-7). These parables are about knowing His Torah.