en_tn/2co/10/18.md

recommends himself

This means that he provides enough evidence for each person who hears him to decide whether he is right or wrong. See how "recommend ourselves" is translated in 2 Corinthians 4:2.

who is approved

This can be stated in active form. Alternate translation: "whom the Lord approves" (See: rc://en/ta/man/jit/figs-activepassive)

but the one whom the Lord recommends

You can make clear the understood information. Alternate translation: "but it is the one whom the Lord recommends who is approved" (See: rc://en/ta/man/jit/figs-ellipsis)