Albert Barnes Commentary 1 Corinthians 2:4

"And my speech and my preaching were not in persuasive words of wisdom, but in demonstration of the Spirit and of power:" — 1 Corinthians 2:4 (ASV)

And my speech. The word speech here—if it is to be distinguished from preaching—refers, perhaps, to his more private reasonings; his preaching, to his public discourses.

Not with enticing words. Not with persuasive reasonings, peithois logois, of the wisdom of men. Not with that kind of oratory that was adapted to captivate and charm, and which the Greeks so much esteemed.

But in demonstration. In the showing, apodeixei, or in the testimony or evidence which the spirit produced.

The meaning is that the spirit furnished the evidence of the Divine origin of the religion which he preached, and that it did not depend for its proof on his own reasonings or eloquence.

The proof, the demonstration which the Spirit furnished, was undoubtedly the miracles which were performed, the gift of tongues, and the remarkable conversions which attended the gospel.

The word Spirit here refers, doubtless, to the Holy Spirit, and Paul says that this Spirit had furnished demonstration of the Divine origin and nature of the gospel. This had been by the gift of tongues (1 Corinthians 2:5–7; compare to 1 Corinthians 14) and by the effects of His agency in renewing and sanctifying the heart.

And of power. That is, of the power of God (1 Corinthians 1:5); the Divine power and efficacy which attended the preaching of the gospel there (compare to 1 Thessalonians 1:5). The effect of the gospel is the evidence to which the apostle appeals for its truth. That effect was seen:

1. In the conversion of sinners to God, of all classes, ages, and conditions, when all human means of reforming them were futile.
2. In its giving them peace, joy, and happiness; and in its transforming their lives.
3. In making them different men—in making the drunkard sober; the thief honest; the licentious pure; the profane reverent; the indolent industrious; the harsh and unkind gentle and kind; and the wretched happy.
4. In its diffusing a mild and pure influence over the laws and customs of society, and in promoting human happiness everywhere.

And in regard to this evidence to which the apostle appeals, we may observe:

1. That it is a kind of evidence which anyone may examine, and which no one can deny. It does not need labored, abstruse argumentation, but it is everywhere in society. Everyone has witnessed the effects of the gospel in reforming the vicious, and no one can deny that it has this power.
2. It is a mighty display of the power of God. There is no more striking exhibition of His power over mind than in a revival of religion. There is nowhere more manifest demonstration of His presence than when, in such a revival, the proud are humbled, the profane are awed, the blasphemer is silenced, and the profligate, the abandoned, and the moral are converted to God, and are led as lost sinners to the same cross, and find the same peace.
3. The gospel has thus demonstrated from age to age that it is from God. Every converted sinner furnishes such a demonstration, and every instance where it produces peace, hope, and joy shows that it is from heaven.