What is Paul driving at about faithfulness in this passage?

Les explains this by comparing faith to sitting in a chair. You did not inspect the chair to see if it would hold you; you simply placed your faith in it, and for it to hold you the chair had to be faithful. In the same way, Christ has claimed to have done everything necessary, and we put our faith in that. Someday in the eternal abode, God will not say it was not what it seemed. The blood of Christ is faithful; He is faithful, and that is why we can trust Him. So Paul is driving at it being through the faithfulness—His faith in the One who is faithful to keep us—and because He loved me and gave Himself for me. Les also stresses that it is not how much we love Him, but how much He has loved us.