Matthew Henry on Matthew 16:1-4

The Pharisees and Sadducees were opposed to each other in principles and in conduct; yet they joined against Christ. But they desired a sign of their own choosing: they despised those signs which relieved the necessity of the sick and sorrowful, and called for something else which would gratify the curiosity of the proud. It is great hypocrisy, when we slight the signs of God's ordaining, to seek for signs of our own devising.