Verses 33-36 are a metaphor where Jesus speaks of his teaching as "light" that he wants his disciples to obey and share with others. He speaks of people who do not know or accept his teaching as being in "darkness." (See: [[rc://en/ta/man/translate/figs-metaphor]])
The understood subject and verb in this clause may be supplied. Alternate translation: "but a person places it on a lampstand" or "but a person puts it on a table" (See: [[rc://en/ta/man/translate/figs-ellipsis]])