God overcame Paul and saved him. Certainly there have been sinners far worse than Paul, but the sense of his thought is that nobody is beyond the reach of God's power to convict of sin and affect dramatic changes of behavior.
John W. Ritenbaugh
The Sovereignty of God: Part Six
Paul uses himself to exemplify the great magnitude of Christ's patience toward us. "Longsuffering" strongly implies forbearance under great duress. As Paul describes it, he had not just sinned in blaspheming and inflicting injury on the saints, but he had done his deeds with a proud, haughty, arrogant, and insolent spirit. He acted in a wicked, malicious, violent way—a spirit of tyranny that greatly aggravated the wrong he did. Other translations render insolent as "insulter," "insolent foe," "oppressor," "wanton aggressor," "doer of outrage," and "wanton outrage."
Paul's aim is to magnify Christ's patience and forgiveness as an example to himself and his audience. The apostle followed Christ's example by in turn exercising patience toward the church. Considering his own circumstance, he undoubtedly felt strongly about this because Christ's forbearance with him opened salvation to him. In response, he passes it on to Timothy and so to us.
In II Timothy 4:2-3, Paul exhorts the evangelist to use this virtue that means so much to our salvation:
Preach the word! Be ready in season and out of season. Convince, rebuke, exhort, with all longsuffering and teaching. For the time will come when they will not endure sound doctrine, but according to their own desires, because they have itching ears, they will heap up for themselves teachers; and they will turn their ears away from the truth, and be turned aside to fables.
John W. Ritenbaugh
The Fruit of the Spirit: Patience
Christ's patient and enduring handling of sinners demonstrates His longsuffering. God promises that He will be long-tempered with us as we repent and dedicate ourselves to the obedience and service of God. As in everything else, Jesus Christ sets the standard of longsuffering.
Martin G. Collins
Other Forerunner Commentary entries containing 1 Timothy 1:16: