About a willingness to believe:

Matthew 23:37 "O Jerusalem, Jerusalem, you who kill the prophets and stone those sent to you, how often I have longed to gather your children together, as a hen gathers her chicks under her wings, but you were not willing. (NIV)

We can explain the principle of leverage. We can calculate the force required to lift a weight with a lever by using the formula for mechanical advantage. The law of leverage will work everywhere on earth. Spiritual belief is not as easily explained as the law of leverage. In regard to our spiritual faith, our willingness to believe is the same as or greater than our ability to believe. Our willingness to believe opens the spiritual door of our heart. Our ability to see, understand, and comprehend all things spiritual is tied directly to our willingness to believe. If we are willing to believe, then doors are opened and the power of God works in spite of our unbelief. If we are willing to believe, our willingness to believe opens the door of our heart and mind to the wondrous power of God. If we are willing to believe, we open the door to the power of God and in Him all things are possible.