I have a water filter attached to my kitchen sink at home. The water normally smells bad, tastes bad, because it has stuff in it. When the water comes into the filter, the filter holds on to all the bad stuff. It doesn’t allow the bad stuff to go on through.
I think our brains have a “filter” too. For example, if a person does not believe in God, and they hear someone tell about something spiritual going on in their lives, this person will dismiss it as coincidence, as chance, because they don’t believe that there is a God who makes that difference in a person’s life. But the opposite is also true. Let’s say that a person believes in God and has a sincere relationship with Jesus, and they hear an unbeliever say something like, “I don’t know why these things are happening to me, but I wish they’d stop.” And because of the believer’s “filter,” they know that God is trying to get that person’s attention.
That filter is made up of what we believe deep down, and it only lets through what we want it to let through.