Let us look also at his next statement, in which he introduces, as it were, a certain person, who, after hearing what has been said, expresses himself in the following manner, “How, then, shall I know God? And how shall I learn the way that leads to Him? And how will you show Him to me? Because now, indeed, you throw darkness before my eyes, and I see nothing distinctly.” He then answers, as it were, the individual who is thus perplexed, and thinks that he assigns the reason why darkness has been poured upon the eyes of him who uttered the foregoing words, when he asserts that “those whom one would lead forth out of darkness into the brightness of light, being unable to withstand its splendours, have their power of vision affected and injured, and so imagine that they are smitten with blindness.”
In answer to this, we would say that all those indeed sit in darkness, and are rooted in it, who fix their gaze upon the evil handiwork of painters, and moulders and sculptors, and who will not look upwards, and ascend in thought from all visible and sensible things, to the Creator of all things, who is light; while, on the other hand, every one is in light who has followed the radiance of the Word, who has shown in consequence of what ignorance, and impiety, and want of knowledge of divine things these objects were worshipped instead of God, and who has conducted the soul of him who desires to be saved towards the uncreated God, who is over all.
For “the people that sat in darkness— the Gentiles— saw a great light, and to them who sat in the region and shadow of death light is sprung up,” — the God Jesus. No Christian, then, would give Celsus, or any accuser of the divine Word, the answer, “How shall I know God?” for each one of them knows God according to his capacity. And no one asks, “How shall I learn the way which leads to Him?” because he has heard Him who says, “I am the way, and the truth, and the life,” and has tasted, in the course of the journey, the happiness which results from it. And not a single Christian would say to Celsus, “How will you show me God?”
Source: Against Celsus (New Advent)