When they sent word to the Lord about Lazarus's sickness, his sisters added no request, leaving the future to the Lord. Sufficit ut noveris, says blessed Augustine on this place, non enim amas et deseris. It is enough that Thou knowest, for Thou lovest and wilt not abandon without help.
Yet in this sending there was a silent plea, and the Lord answers the thoughts of those who sent it. Of course everything was known to the Lord. Yet, remaining within the bounds of human life, He first hears the messenger's words and then replies.
He does this so that His words may be carried back as consolation to Lazarus's sisters by the messenger, who was to return at once. The Lord answers: "This sickness is not unto death, but for the glory of God, that the Son of God may be glorified."
The whole of chapter 11 has this meaning, as St. John Chrysostom indicates in Homily 62 on John. The Lord's delay in the place where He was, and His arrival only after Lazarus's death, had one aim.
They were to impress more deeply and powerfully upon the minds of the disciples and of the Jews who had come to Bethany the meaning of the miracle, the majesty of Him who performed it, and His complete identity with the Father.
"I and the Father are one," He had said, and the Jews took up stones. Here many of those same Jews would be present at an event that can be understood and named only as an act of creation.
The words spoken by the Lord in Perea, or beyond the Jordan, to the messenger had to awaken faith in the sick man's relatives and in those who heard. The messenger had to return to Bethany two days before the Lord. Verse 6 says that the Lord remained in the place two days, while the messenger of course returned immediately. If he walked quickly, and perhaps even rode, he could have arrived three or four days before the Lord. Compare v. 17 and the explanation.
Those words also had to set this faith to the test. Yet the Lord was preparing weak men for great joy. This joy was not in Lazarus's resurrection alone, for that was a secondary feeling.
Great joy seized the hearts of the disciples and Lazarus's sisters when they saw the glory of God overshadowing the Lord Jesus. Every wavering of their soul vanished like marsh mist scattered by the brightness of the sun.
"If you believe, you will see the glory of God," the Lord said to Martha, v. 40.