Note that the verb in the second part of the verse, “is” for KJV and “brings” in the NASB are assumed. Notice they are printed in italics which means they are not in the Hebrew. Substitute a comma and see how that works for you,
(Pro 13:17 KJV) A wicked messenger falleth into mischief: but a faithful ambassador, health.Now notice the first verb, “falls” (5307), which is a very common word in the Old Testament. In Proverbs is seems to have a negative connotation. That may be why it is left out of the second part. Either way this points to a natural result of our intent and discipline.
So? One message of the Bible is that God honors those who seek to be righteous. Good deeds won’t earn us salvation but will help to get God to smile in our direction.