Jesus told his disciples in order to have a "witness" (a reputation worth listening to), they have to do "good deeds". But Jesus then later tells his followers to do their "good deeds" in private. The "good deeds" Jesus did and was telling his followers to practice were BOTH private and Public...they lived by the same standard/conviction everywhere they went. The "good deeds" Jesus did were also unpopular...angering people to the point they attempted several times to kill him,...and eventually did...this should tell us something about what Matthew intends with the words "Good Deeds".