This chapter illustrates a progression of light that occurs in every believer who comes from the relative darkness of Judaism to the superior light of Christianity (“day dawn” – 2 Peter 1:19). John noted this transition in his epistle and said, "The darkness is passing and the true light already shines" (1 John 2:8).
The Lord announced that He was "the Light of the world" (vs. 5), but the spiritual darkness that prevailed over the people was such that they could not see it. Natural light dispels natural darkness, but spiritual light does not dispel spiritual darkness (John 1:5). It does, however, bring out the moral incapacity of man. The condition of the man in this chapter who was "born blind" illustrates this. What the Lord did for him depicts the work of God in souls that enables them to see Christ for who He is. In seeing Christ as the Son of God, the man no longer needed the Jewish system of approach to God in worship. This is demonstrated by him worshipping the Lord outside the temple (vs. 38). Thus, Scripture teaches that this “new and living way” in Christianity is “without the camp” of Judaism (Heb. 10:19-22; 13:13-15).
This all came about by the Lord spitting on the ground and making "clay," which signified the great truth of His incarnation (vs. 6). Spit coming forth from Himself as God and mixed with "the dust of the ground" (which speaks of humanity – Gen. 2:7; 3:19) points to the Son of God becoming a Man—His incarnation. The application of the “spittle” to the eyes of the blind man speaks of the quickening power of God imparting life to a person by which the spiritual faculty of understanding divine things is opened (Prov. 20:16; Acts 26:18; Eph. 4:17-18). The washing in "the pool of Siloam (which is by interpretation, Sent)" speaks of a believer understanding that the Lord Jesus is the Sent One of the Father (vs. 7). This is a distinctly Christian revelation.
After getting his eyes open, there was a progression of light and understanding in the man who was born blind—he went from begging (vs. 8) to worshipping (vs. 38). His experience depicts the transition through which the faithful in the old legal system go in coming into Christian knowledge and liberty. At first, all he knew of the Lord was that He was "a man that is called Jesus." He didn't know who He was or where He came from (vs. 11). Then, upon being questioned, he said, "He is a Prophet" (vs. 17). Then after that, the man saw the Lord to be worthy of having "disciples" (vss. 27-28). Then, he told the Jews that the Lord Jesus was a man "of God" (vs. 33). Finally, he saw the Lord as "the Son of God," whom He truly was (vss. 35-38). Thus we see in this man's experience a marvelous transition from darkness to light. In the process, the man suffered persecution from the Jews. This shows that those who walk in the light of the new dispensation will be persecuted by those of the old (Acts 13:50; 14:19; 17:5, 13; 1 Thess. 2:14-16).