The Scripture is clear that God’s nature and character are eternally unchangeable: He will never lie; He will never go back on a promise; He will never be overthrown; He will never abandon us; He will always be loving; He will always be righteous; He will always be merciful and He will always be just. (see Num 23:19; Isa 46:9-11) And yet there are various instances in the Scriptures where God changes His proposed course of action. For example, on two different occasions He announced to Moses that He would destroy the people of Israel, only then to be persuaded not to do so. (Ex 32:7-14; Num 14) As a result of Moses’s prayer, YHWH “repented of the disaster that he had spoken of bringing on his people.” (Ex 32:14)
So the Bible is clear that prayer can change God’s course of action. His character will never change, but His plans will change according to what we do and say.
This was how the Hebrew prophets viewed God. Abraham Heschel writes that the God of the Old Testament is “moved and affected by what happens in the world, and reacts accordingly. Events and human actions arouse in Him joy or sorrow, pleasure or wrath . . . Man’s deeds may move Him, affect Him, grieve Him or, on the other hand, gladden and please Him. This notion that God can be intimately affected, that He possesses not merely intelligence and will, but also pathos, basically defines the prophetic consciousness of God.” (The Prophets, 289)
One of the most famous passages in Scripture on the power of prayer is found in 2 Chronicles 7:13-15.  As Solomon dedicated the Temple, God spoke to him promising that the prayers lifted up in that place would have the power to persuade Him:  "When I shut up the heavens so that there is no rain, or command the locust to devour the land, or send pestilence among my people, if my people who are called by my name humble themselves, and pray and seek my face and turn from their wicked ways, then I will hear from heaven and will forgive their sin and heal their land. Now my eyes will be open and my ears attentive to the prayer that is made in this place."
This passage makes it very clear that prayer has the power to influence God. He is affected by what we say and what we do. We can never persuade God to do something that is contrary to His nature and character. But as long as we are seeking the good; as long as we are asking for the fuller display of His mercy, His love and His saving power – our prayers can persuade God to take a course of action that He might not have otherwise chosen.
In the next post we will look how this perspective on God's openness to change was articulated in the New Testament.