Jesus uses this proverb to begin to tell them that he calls sinners to repentance the way a physician calls sick people to be healed. (See: [[rc://en/ta/man/jit/writing-proverbs]])
You may need to supply the words that have been omitted. Alternate translation: "only those who are sick need a physician" (See: [[rc://en/ta/man/jit/figs-ellipsis]])