en_tn/mat/23/15.md

you go over sea and land

This is an idiom that means they go to distant places. Alternate translation: "you travel great distances" (See: rc://en/ta/man/translate/figs-idiom)

to make one convert

"to make one person accept your religion"

son of hell

Here "son of" is an idiom that means "one belonging to." Alternate translation: "person who belongs in hell" or "person who should go to hell" (See: rc://en/ta/man/translate/figs-idiom)