This metaphor means that the child will help people to understand God's will. The Gentiles understanding God's will is spoken of as if they were people using physical light to see a solid object. You may need to make explicit what it is that the Gentiles will see. Alternate translation: "This child will enable the Gentiles to understand God's will as light allows people to see clearly" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-explicit]])
It may be necessary to state what is to be revealed. Alternate translation: "that will reveal God's truth" (See: [[rc://en/ta/man/translate/figs-explicit]])