John Calvin Commentary 2 Peter 3:16

"as also in all [his] epistles, speaking in them of these things; wherein are some things hard to be understood, which the ignorant and unstedfast wrest, as [they do] also the other scriptures, unto their own destruction." — 2 Peter 3:16 (ASV)

In which are some things. The relative which does not refer to epistles, because it is in the neuter gender. The meaning is that in the things which he wrote there was sometimes an obscurity, which caused the unlearned to go astray to their own ruin. We are reminded by these words to reason soberly on things so high and obscure. Furthermore, we are strengthened against this kind of offense, so that the foolish or absurd speculations of men do not disturb us—speculations by which they entangle and distort simple truth, which should serve for edification.

But we must observe that we are not forbidden to read Paul's Epistles because they contain some things hard and difficult to understand; on the contrary, they are commended to us, provided we bring a calm and teachable mind. For Peter condemns men who are frivolous and unstable, who strangely turn to their own ruin what is useful to all. Indeed, he says that this is commonly done concerning all the Scripture. Yet he does not from this conclude that we are not to read it; he only shows that those vices should be corrected which not only prevent improvement but also make deadly for us what God has appointed for our salvation.

It may, however, be asked, "From where is this obscurity, since the Scripture shines to us like a lamp and guides our steps?" To this I reply that it is not surprising if Peter ascribed obscurity to the mysteries of Christ's kingdom, especially if we consider how hidden they are to the perception of the flesh. However, the mode of teaching which God has adopted has been so regulated that all who do not refuse to follow the Holy Spirit as their guide find in the Scripture a clear light. At the same time, many are blind who stumble at midday; others are proud, who, wandering through devious paths and flying over the roughest places, rush headlong into ruin.