Blessed are they who have not seen and yet have believed.

Nothing is more common now-a-days than to hear people say that they “decline to believe things above their reason, that they cannot believe what they cannot entirely understand in religion, that they must see everything clearly before they can believe.” Such talk as this sounds very fine, and is very taking with young persons and superficially educated people, because it supplies a convenient reason for neglecting vital religion altogether. But it is a style of talking which shows a mind either proud, or foolish, or inconsistent.  In matters of science, what sensible man does not know that we must begin by believing much that we do not understand, taking many positions on trust, and accepting many things on the testimony of others? Even in the most exact science the scholar must begin with axioms and postulates.  Faith and trust in our teachers is the very first condition of acquiring knowledge. He who begins his studies by saying “I shall not believe anything which I do not see clearly demonstrated from the very first,” will make very little progress.

In the daily business of life, what sensible man does not know that we take many important steps on no other ground than the testimony of others?  Parents send sons to Australia, New Zealand, China, and India without ever having seen these countries, in faith that the report about them is dependable and true. Probability, in fact, is the only guide of most parts of our life.

In the face of such facts as these, where is the common sense of saying, as many rationalists and skeptics now do, that in such a mysterious matter as the concern of our souls we ought to believe nothing that we do not see, and ought to receive nothing as true that will not admit of mathematical demonstration? Christianity does not at all refuse to appeal to our intellects, and does not require of us a blind, unreasoning faith. But Christianity does ask us to begin by believing many things that are above our reason, and promises us that, so beginning, we shall have more light and see all things clearly. The would-be wise man of modern times says, “I dislike any religion that contains any mystery. I must first see and then I will believe.” Christianity replies, “You cannot avoid mystery, unless you go out of the world. You are only asked to do with religion what you are always doing with science. You must first believe and then you will see.” The cry of the modern skeptic is, “If I could see I would believe.” The answer of the Christian ought to be, “If you would only believe and humbly ask for Divine teaching, you would soon see.” The plain truth is that modern freethinkers are like the Jews, who were always demanding some visible sign that our Lord was the Messiah, and pretended that they would believe if they only saw it. Just in the same way there are hundreds of people in this latter age of the world who tell us they can believe nothing which is above their reason, and that they want stronger evidences of the truth of the doctrine and fact of Christianity than probability. Like Thomas, they must first see before they believe.  But what an extraordinary fact it is that the very men who say all this are continually acting all their lives on no better evidence than probability!  They are continually doing things on no other ground than the report of others and their own belief that this report is probably true. The very principle on which they are incessantly acting, in the affairs of their bodies, their families, and their money, is the principle on which they refuse to act in the affairs of their souls! In the things of this world they believe all sorts of things which they have not seen and only know to be probable, and act on their belief. In the things of the eternal world they say they can believe nothing which they do not see, and refuse the argument of probability altogether. Never, in fact, was there anything so unreasonable and inconsistent as rationalism, so called! No wonder that our Lord laid down, for the benefit of Thomas and the whole Church, that mighty principle, “Blessed are they who have not seen and yet have believed.” [John 20:29]

—J.C. Ryle, 'Expository Thoughts on John’