John 1:7

The same came for a witness
The end of his being sent, and the design of his coming were,

to bear witness of the light:
by which is meant, not the light of nature, or reason; nor the light of the Gospel: but Christ himself, the author of light, natural, spiritual, and eternal. This was one of the names of the Messiah with the Jews; of whom they say ^F21, (wmv aryhn) , "light is his name"; as it is said in ( Daniel 2:22 ) and the light dwelleth with him; on which they have ^F23 elsewhere this gloss, this is the King Messiah; and so they interpret ( Psalms 43:3 ) of him ^F24. Philo the Jew often speaks of the Logos, or word, as light, and calls him the intelligible light; the universal light, the most perfect light; represents him as full of divine light; and says, he is called the sun ^F25. Now John came to bear a testimony to him, as he did; of which an account is given in this chapter, very largely, and elsewhere; as that he testified of his existence before his incarnation; of his being with the Father, and in his bosom: of his deity and divine sonship; of his being the Messiah; of the fulness of grace that was in him; of his incarnation and satisfaction; of his descent from heaven; and of his relation to his church, as in ( John 1:15 John 1:16 John 1:18 John 1:23 John 1:27 John 1:29 John 1:30 John 1:34 John 1:36 ) ( John 3:29 John 3:31 ) the end of which witness was,

that all men through him might believe;
that is, that the Jews, to whom he preached, might, through his testimony, believe that Jesus was the light, and true Messiah; for these words are to be taken in a limited sense, and not to be extended, to every individual of mankind; since millions were dead before John began his testimony, and multitudes then in being, and since, whom it never reached: nor can it design more than the Jews, to whom alone he bore witness of Christ; and the faith which he taught, and required by his testimony, was an assent unto him as the Messiah; though the preaching of the Gospel is a means of true spiritual faith in Christ; and doubtless it was so to many, as preached by John: it points out the object of faith, and encourages souls to believe in Christ; and hence, Gospel ministers are instruments by whom ethers believe; and faith comes by hearing, and hearing by the word of God; and then is it, considerable end of the Gospel ministry answered.