Over the previous few verses, Paul has presented a very brief, yet extremely encouraging synopsis of the gospel message. With this verse, he concludes that thought, before moving on to some final instructions to Titus.
You can find this passage in Titus 3:8:
This marks the fifth occurrence of a “trustworthy saying” in Paul’s three Pastoral Epistles. The other four are found in Paul’s letters to Timothy: 1 Timothy 1:15, 3:1, 4:9, and 2 Timothy 2:11. In this instance, Paul is stating that the previous statements concerning God’s grace are reliable and trustworthy. As a result, those who believe, both on Crete and for us today, must live accordingly.
Also, Paul intends for Titus to “stress these things.” Again, this most definitely refers to the previous thoughts concerning God’s saving work, but may also be broad enough to include all of the instructions that Paul has given Titus to pass on to the believers on Crete.
Because of this, this passage may very well be a summary statement of the entire letter to Titus. And Paul’s verb usage here is emphatic. Titus’ job is to stress these things, and to do so with the urgency necessary for people to understand this saving grace of God as quickly as possible.
The result of all of this is that the people who have turned to God will display their faith in the things that they do. And they will be a benefit to everyone.