Ps 111 His precepts are sure.

John MacArthur writes: Two polar opposite views of God’s will can cause Christians to have faulty understandings of prayer and the accomplishing of God’s purposes. The same can be said for how people view the character of God. On the one hand, some believe the words of the song “que sera sera” or whatever will be will be, and on the other hand, some see that God will hear prayer and as the king of Nineveh said, “Who knows? Perhaps God might be willing to change his mind and relent and turn from his fierce anger so that we might not die.” [Jonah 3:9]

One thing is certain; God is immutable; He is unchanging. However, like the mercury in a thermometer, He “changes” according to the “mercury” of men’s hearts. The author of Hebrews notes: that his purposes are unchangeable, and it is impossible for God to lie. [Heb 6:17-18] His precepts are sure; we can trust that what God says will always be true. Men may change, but God is immutable.