I respond in two ways: (1) their burdened heart about their spiritual state IS evidence of the Spirit’s work within them; and (2) 2 Pet 1:3-11 is one of the most crucial texts for helping doubting believers. When assurance is elusive, Peter declares what we’ve been “granted” in Christ, and then he calls the doubter to tap into the power of the Spirit by moving forward in diligent faith. Peter assures us that when we press forward in faith, the Spirit produces the moral fruit that gives evidence that Christ has indeed granted life to us, and assurance is strengthened. In our ministry, this text has become a life-changer for so many. In today’s church culture, Peter would be labeled a discourager and law-preacher. But assurance IS NOT fortified MERELY by clinging to the cross. YES, our salvation IS Christ’s work from start to finish! We can trust that reality and be assured within us by faith. BUT the cross of Christ provides power over sin, which Peter says we should diligently access for strengthening assurance. “When these qualities are yours and are increasing” we become “fruitful in the true knowledge of our Lord Jesus Christ.” The Spirit deepens assurance as He empowers us to Christlike holiness. Telling doubters over and over that Christ did it all for them while neglecting to help them access divine power by diligent faith is discouraging. They need to experience Christ’s power over their sin. He’s promised it. Help the doubter diagnose where their faith is least diligent and walk with them toward a greater trust in all that we’ve been granted. They will begin to experience an increasing Christlikeness, and their assurance will deepen. It will NEVER be perfect. Battling sin and striving for holiness IS our privilege in the power of Christ. And amazingly, our meager offerings of obedience never diminishes His love for us! But He’s promised His power. He’s granted it. We have THAT guarantee within us! So “we press on” in His power.