Titus 2:1; Titus 2:7-8

1 But let your words be in agreement with true and right teaching:
7 In all things see that you are an example of good works; holy in your teaching, serious in behaviour, 8 Saying true and right words, against which no protest may be made, so that he who is not on our side may be put to shame, unable to say any evil of us.