Why is this surprising? They learned from the best.
John 12 40 He has blinded their eyes and deadened their hearts, so they can neither see with their eyes, nor understand with their hearts, nor turn–and I would heal them.
2 Thessalonians 2 11 For this reason God sends them a powerful delusion so that they will believe the lie 12 and so that all will be condemned who have not believed the truth but have delighted in wickedness.
Mark 4 10 When he was alone, the Twelve and the others around him asked him about the parables. 11 He told them, “The secret of the kingdom of God has been given to you. But to those on the outside everything is said in parables 12 so that, “ ‘they may be ever seeing but never perceiving, and ever hearing but never understanding; otherwise they might turn and be forgiven!’"
Joshua 11 19 Except for the Hivites living in Gibeon, not one city made a treaty of peace with the Israelites, who took them all in battle. 20 For it was the LORD himself who hardened their hearts to wage war against Israel, so that he might destroy them totally, exterminating them without mercy, as the LORD had commanded Moses.