John Calvin Commentary 2 Timothy 3:13

"But evil men and impostors shall wax worse and worse, deceiving and being deceived." — 2 Timothy 3:13 (ASV)

But wicked men and impostors—this is the most bitter of all persecutions, when we see wicked men, with their sacrilegious boldness, with their blasphemies and errors, gathering strength. Thus Paul says elsewhere that Ishmael persecuted Isaac, not by the sword, but by mockery (Galatians 4:29). From this, we may also conclude that in the preceding verse, it was not merely one kind of persecution that was described, but that the Apostle spoke in general terms of those distresses which the children of God are compelled to endure when they contend for the glory of their Father.

I stated earlier in what respect they shall grow worse and worse; for he foretells not only that they will make obstinate resistance, but that they will succeed in injuring and corrupting others. One worthless person will always be more effective in destroying than ten faithful teachers in building, though they labor with all their might. Nor are the tares which Satan sows to injure the pure corn ever lacking; and even when we think that false prophets are driven away, others continually spring up in other directions.

Again, as to the power of doing injury, it is not because falsehood, by its own nature, is stronger than truth, or that the tricks of Satan exceed the energy of the Spirit of God; but it is because men, being naturally inclined to vanity and errors, more readily embrace what agrees with their natural disposition, and also because, being blinded by a righteous vengeance of God, they are led, as captive slaves, at the will of Satan.

And the chief reason why the plague of wicked doctrines is so effective is that the ingratitude of men deserves it. It is highly necessary for godly teachers to be reminded of this, so that they may be prepared for uninterrupted warfare, and may not be discouraged by delay, or yield to the haughtiness and insolence of adversaries.