Jesus said unto him, If thou canst believe, all things are possible to him that believeth. (Mark 9:23)
Our unbelief is the greatest hindrance in our way; in fact, there is no other real difficulty as to our spiritual progress and prosperity. The Lord can do everything; but when He makes a rule that according to our faith so shall it be unto us, our unbelief ties the hands of His omnipotence.
Yes, the confederacies of evil shall be scattered if we can but believe. Despised truth shall lift its head if we will but have confidence in the God of truth. We can bear our load of trouble or pass uninjured through the waves of distress if we can gird our loins with the girdle of peace, that girdle which is buckled on by the hands of trust.
What can we not believe? Is everything possible except believing in God? Yet He is always true; why do we not believe in Him? He is always faithful to His word; why can we not trust Him? When we are in a right state of heart, faith costs no effort: it is then as natural for us to rely upon God as for a child to trust his father.
The worst of it is that we can believe God about everything except the present pressing trial. This is folly. Come, my soul, shake off such sinfulness, and trust thy God with the load, the labor, the longing of this present. This done, all is done.
C.H. Spurgeon, Faith’s Checkbook