Faith - properly understood - is not a feeling. Rather, faith is active trust based on evidence. Of course, faith can affect how we feel. For example, my trust in my wife may produce feelings of happiness and gratitude, while mistrust can produce feelings of sadness and betrayal.
So faith and feelings are related, but different. Unfortunately, some people base their faith on their feelings. Consequently, the good feelings they get from praying, worshiping, or attending church lead them to conclude their faith is true. In this case, faith is held hostage by feelings.
This is extremely dangerous because feelings are fickle - they can change from day to day. The psalmist David knew this very well. In Psalm 73, he describes how he was feeling “envious of the arrogant” because of “the prosperity of the wicked” (Ps. 73:3). Moreover, he writes,
They scoff and speak with malice;
loftily they threaten oppression.
They set their mouths against the heavens,
and their tongue struts through the earth.
Therefore his people turn back to them,
and find no fault in them.
And they say, “How can God know?
Is there knowledge in the Most High?”
Behold, these are the wicked;
always at ease, they increase in riches.
All in vain have I kept my heart clean
and washed my hands in innocence.
For all the day long I have been stricken
and rebuked every morning.
When David’s feelings are left unchecked, he begins questioning his faith. Notice again verse 13. In a moment of emotional weakness, he declares that his faithfulness to God was “all in vain.”
However, David doesn’t let his feelings steer his faith. In fact, it’s just the opposite. David’s faith in God governs his feelings. He writes,
Nevertheless, I am continually with you;
you hold my right hand.
You guide me with your counsel,
and afterward you will receive me to glory.
Whom have I in heaven but you?
And there is nothing on earth that I desire besides you.
My flesh and my heart may fail,
but God is the strength of my heart and my portion forever.
At the end of the day, David doesn’t know why God allows the wicked to prosper. God never tells him. But he doesn’t allow his emotions - envy in this case - to get the better of him. He trusts in the God who has guided his life and has continually shown Himself faithful.
Feelings have their proper place in the Christian life. After all, God created them. But since they are far too easily influenced, and far too influential, they must not be allowed to instruct faith. Instead, faith instructs our feelings.
This same point is made by C. S. Lewis in Mere Christianity. He states,
Now Faith, in the sense in which I am here using the word, is the art of holding on to things your reason has once accepted, in spite of your changing moods.
That’s it exactly. Reason assesses what is true, and faith holds on to it. And when moods rise up to confront and challenge our faith, we correct them. Lewis goes on to say,
For moods will change, whatever view your reason takes. I know that by experience. Now that I am a Christian I do have moods in which the whole thing looks very improbable: but when I was an atheist I had moods in which Christianity looked terribly probable. This rebellion of your moods against your real self is going to come anyway. That is why Faith is such a necessary virtue: unless you teach your moods ’where they get off,’ you can never be either a sound Christian or even a sound atheist, but just a creature dithering to and fro, with its beliefs really dependent on the weather and the state of its digestion. Consequently one must train the habit of Faith.
If feelings don’t inform faith, then what does? Biblical faith is informed by evidence. Jesus said, “Even though you do not believe me, believe the works” (John 10:38). What works is He talking about? The blind are seeing. The lame are walking. The deaf are hearing. The dead are rising. He is saying, “Believe based on the objective evidence.”
Emotions can be unreliable guides to the truth. But evidence doesn’t lie.
So feelings follow faith, and faith follows facts. For instance, my wife tells me daily that she loves me and does all kinds of things to show me. Those are the facts. These facts - and others - form the basis of my faith in her. And out of that faith comes feelings like joy, love, and safety. Similarly, there are facts about the life, death, and resurrection of Christ that form the basis of my faith in Christ. And out of that faith comes feelings of gratitude, humility, joy, and hope.