From a treatise on John by Saint Augustine, bishop
Christ is the way to the light, the truth, and the life

The Lord tells us: I am the light of the world; he who follows me will not walk in darkness, but will have the light of life. In these few words he gives a command and makes a promise. Let us do what he commands so that we may not blush to covet what he promises and to hear him say on the day of judgment: “I laid down certain conditions for obtaining my promises. Have you fulfilled them?” If you say: “What did you command, Lord our God?” he will tell you: “I commanded you to follow me. You asked for advice on how to enter into life. What life, if not the life about which it is written: With you is the fountain of life?”

Let us do now what he commands. Let us follow in the footsteps of the Lord. Let us throw off the chains that prevent us from following him. Who can throw off these shackles without the aid of the one addressed in these words: You have broken my chains? Another psalm says of him: The Lord frees those in chains, the Lord raises up the downcast.

Those who have been freed and raised up follow the light. The light they follow speaks to them: I am the light of the world; he who follows me will not walk in darkness. The Lord gives light to the blind. Brethren, that light shines on us now, for we have had our eyes anointed with the eye-salve of faith. His saliva was mixed with earth to anoint the man born blind. We are of Adam’s stock, blind from our birth; we need him to give us light. He mixed saliva with earth, and so it was prophesied: Truth has sprung up from the earth. He himself has said: I am the way, the truth, and the life.

We shall be in possession of the truth when we see face to face. This is his promise to us. Who would dare to hope for something that God in his goodness did not choose to promise or bestow?
We shall see face to face. The Apostle says: Now I know in part, now obscurely through a mirror, but then face to face. John the apostle says in one of his letters: Dearly beloved, we are now children of God, and it has not yet been revealed what we shall be. We know that when he is revealed we shall be like him, for we shall see him as he is. This is a great promise.

If you love me, follow me. “I do love you,” you protest, “but how do I follow you?” If the Lord your God said to you: “I am the truth and the life,” in your desire for truth, in your love for life, you would certainly ask him to show you the way to reach them. You would say to yourself: “Truth is a great reality, life is a great reality; if only it were possible for my soul to find them!”