Final answer:
The Gospel of Matthew was tough on Jewish leaders, particularly the Pharisees and the Sadducees, for their hypocrisy and failure to live up to the true spirit of the law.
Step-by-step explanation:
The gospel that was tough on Jewish leaders was the Gospel of Matthew. In this gospel, Matthew portrays Jesus strongly criticizing the Jewish leaders of his time, particularly the Pharisees and the Sadducees, for their hypocrisy and failure to live up to the true spirit of the law. Jesus condemns their actions and teachings, calling them out for their oppressive behavior and lack of compassion.