en_tn_condensed/jhn/09/39.md

came into this world

The "world" is a metonym for "the people who live in the world." AT: "came to live among the people of this world" (See: rc://en/ta/man/translate/figs-metonymy)

so that those who do not see may see and so that those who see may become blind

Here "seeing" and "blindness" are metaphors. Jesus distinguishes between people who are spiritually blind and physically blind. AT: "so that those who are blind spiritually, but who want to see God, can see him, and those who already falsely think they can see God will remain in their blindness" (See: rc://en/ta/man/translate/figs-metaphor)

Are we also blind?

"Do you think we are spiritually blind?"

If you were blind, you would have no sin

Here "blindness" is a metaphor for not knowing God's truth. AT: "If you wanted to know God's truth, you would be able to receive your sight. (See: rc://en/ta/man/translate/figs-metaphor)

but now you say, 'We see,' so your sin remains

Here "seeing" is a metaphor for knowing God's truth. AT: "Since you falsely think that you already know God's truth, you will remain blind" (See: rc://en/ta/man/translate/figs-metaphor)