The Lord was filled with a holy anger. This was righteous. As the holy Son of God, He burned with God's holy anger against the heinous offense of the hardness of heart, of the unbelief, of the smugness of human pride. The Pharisees and scribes stood before the Messiah who had come to do the work of the Lord. It is an evil thing to be smug about yourself, to imagine that you are not desperately evil and in need of the grace of God, to be content in yourself, to be filled with pride.
Pride is something that is vile and evil.
What the Pharisees were doing as they stood by in the hardness of their hearts, tempting the Lord to heal on the Sabbath day, was an ungodly thing. The Pharisees stood inflexible in their unbelief. They were resolved to persist in their folly of rejecting God's Son. Christ's feeling of anger was a pure and holy passion, rooted in the deepest hatred of sin and in zeal for His Father's glory. Christ's anger was His holiness, clad in robes of justice.