When we think about God, it's important for us to remember that God is not like us. When we try to use human categories to understand the Creator of all things, we reduce Him to something significantly lesser than what He truly is - and in so doing, we make Him less than God.
One of the areas where we see this occur most prominently is when we consider God's emotions. There are various places in Scripture where we see God described as responding to things in what we would understand to be emotional ways.
“You shall say to them this word: ‘Let my eyes run down with tears night and day, and let them not cease, for the virgin daughter of my people is shattered with a great wound, with a very grievous blow." (Jeremiah 14:17)
"And the people complained in the hearing of the LORD about their misfortunes, and when the LORD heard it, his anger was kindled, and the fire of the LORD burned among them and consumed some outlying parts of the camp." (Numbers 11:1)
At the same time, we must reconcile these passages with the reality that Scripture plainly teaches that God does not change, which is a doctrine known as Immutability.
We find this in:
“For I the LORD do not change; therefore you, O children of Jacob, are not consumed." (Malachi 3:6)
Our emotions are definite indicators of change. We feel a certain way for a time, and then we feel differently.
Further, because God is unable to change, this also means that God cannot be acted upon by anything outside of Himself to induce change in Him. Often, our emotions are stirred by things that are outside of our control. The actions of another person can hurt us emotionally or bring about happiness. Even things like movies or music can bring about emotional change. However, God's immutability tells us this is not something that occurs in God.
All of this leads us to the doctrine that has historically been known as God's Impassibility, which literally means "without passions." At it's root, this doctrine helps us to understand that God does not experience emotional change in any way. This sets the true God apart from the false gods that have been invented by man throughout history, who are gods that are susceptible to emotional fluctuation, overcome by a variation in mood, gods changed or manipulated by the will of another. One minute they are given to lust and the next fly off the handle in a fit of rage. But, as Thomas Weinandy shows us, the Christian God stands in contrast because He "does not undergo successive and fluctuating emotional states; nor can the created order alter Him in such a way so as to cause Him to suffer any modification or loss.”
This does not mean that God does not have emotions altogether, but ultimately that He does not experience them as we do. He does not have human emotions, but rather our emotions are a lesser representation of God's nature. Think, for example, of His love. God IS love, and as such His love is not subject to emotional whims. He does not merely possess love that could grow, lessen, or shift, but is instead infinitely love that is unchanging and unceasing. Thus, though He is infinitely angry and wrathful toward sin, He looks upon us in love because of His infinite love for Christ, who is our life.
So when we see in Scripture what appear to be the fluctuating emotions of God, we must remember that there are two things taking place.
First, the Bible is bringing God to a level that makes Him more accessible to us. This is why we see the Bible telling us things like God inclining His ear or covering us with His hand, when we know that He is not a physical being with physical characteristics.
Second, the emotions of God are things that are eternally existing in infinite amounts and are rooted strictly in His own character rather than in the actions of His creation. In other words, God is eternally, infinitely angry at sin. This is expressed in His eternal wrath. He does not get more angry at our individual sins, but instead is acting always in accordance with His own nature. Nothing we do is causing God to react emotionally, or even to have those emotions in the first place.
This is of vital importance for us to understand, because a God who can change is not a God who can be depended on. What happens if we sin too much and in His anger He decides that He no longer wants to keep His promises? It's hard to think of a more dreadful thought. But because we know that God is immutable and impassible, He can be trusted in our times of trouble and suffering, because He is who He is and will never change for any reason.