In Isaiah 1:18, this signifies to think interiorly in either truth or falsity. (Arcana Coelestia 118)

In Daniel 4:34, this signifies a state of insincere acknowledgment and worship of the Lord, before people under obedience to them. (The Inner Meaning of the Prophets and Psalms 175)

In Matthew 16:8, this signifies to have little faith and so to question. (Apocalypse Explained 569)