John Calvin Commentary 1 Corinthians 10:12

"Wherefore let him that thinketh he standeth take heed lest he fall." — 1 Corinthians 10:12 (ASV)

Wherefore let him that thinketh he standeth. The Apostle concludes from what has been said previously that we must not glory in our beginnings or progress, so that we resign ourselves to carelessness and inactivity. For the Corinthians gloried in their condition in such a way that, forgetting their weakness, they fell into many sins. This was a false confidence of the kind that the Prophets frequently reprove in the Israelite people. However, since Papists twist this passage to maintain their impious doctrine that faith constantly has doubt connected with it, let us observe that there are two kinds of assurance.

The one kind of assurance is that which rests on the promises of God, because a pious conscience feels assured that God will never fail it. Relying on this unconquerable persuasion, it triumphs boldly and intrepidly over Satan and sin; yet, keeping in mind its own infirmity, it casts itself upon God and with careful concern commits itself to Him. This kind of assurance is sacred and is inseparable from faith, as appears from many passages of Scripture, and especially Romans 8:33.

The other kind arises from negligence, when people, puffed up with the gifts they have, show no concern, as if they were beyond the reach of danger, but rest satisfied with their condition. Hence, they are exposed to all the assaults of Satan. This is the kind of assurance that Paul wanted the Corinthians to abandon, because he saw that they were satisfied with themselves under the influence of a foolish conceit. He does not, however, exhort them always to be anxiously in doubt about God's will, or to tremble from uncertainty about their salvation, as Papists dream.

In short, let us bear in mind that Paul is here addressing persons who were puffed up with a base confidence in the flesh, and he represses that assurance which is grounded on human beings—not on God. For after commending the Colossians for the solidity or steadfastness of their faith (Colossians 2:5), he exhorts them to be rooted in Christ, to remain firm, and to be built up and
confirmed in the faith (Colossians 2:7).