Everybody knows that growth is a process. When a child is born, it is not immediately a full-grown adult with a lifetime of experiences crammed into its cranium while in the womb. The weakest and most helpless of all newborn things must be a human baby. It has to be taken care of completely and totally by its mother and father, or it would die.
When they are born, most other mammals are at least able to find a way to get something to eat. However, human babies are absolutely helpless. Even though they grow very rapidly—especially in the first few years—during which time they accumulate a great deal of knowledge and experience, their growth is little by little.
Here, right in the Word of God, we are being told that we, too, are to grow! We are not instantaneously a canister full of all kinds of facts and figures and the knowledge of God. We do not understand all the biblical principles. We certainly do not have all wisdom. We know very well that these things accumulate over many years of living.
John W. Ritenbaugh
The Covenants, Grace, and Law (Part 19)
Peter ends the epistle with the same thought with which he began: We live in spiritually dangerous times, and the way to stay on the beam is to keep on growing. If we grow, our salvation is assured. God is faithful; He has promised us salvation, and He will give it to us if we are faithful.
Richard T. Ritenbaugh
Do We Have 'Eternal Security'?
Verse 18 makes it clear that there is a contrast. Peter says, ". . . but grow." Verse 17 is a warning: ". . . beware lest you also fall . . . being led away with the error of the wicked."
The command is to grow, so if the contrast that he is establishing in our minds is to be met, the positive part of the instruction is that effort has to be made in order to grow. If we are not making an effort to grow, the only alternative is to go in reverse. We begin to degenerate if we do not make an effort to grow.
II Peter 3:17 (Moffatt) Now, beloved, you are forewarned: mind you that you are not carried away by the error of the lawless and so lose your proper footing;
My attention is on this verse 17 where he says, "mind you," rather than "beware." He turns it into something that is positive. "Beware" could mean to just look around to make sure that one is safe. But "mind you" says, "Hey, turn your attention to focus on this!"
We can see from the combination of these two verses that effort must be made to produce growth or we will likely fall into the error of the wicked. In other words, doing nothing regarding our spiritual responsibilities is akin to doing nothing regarding our physical responsibilities pertaining to our physical health.
So we are faced with a choice. We are forewarned. Something has to be done; we cannot just stand still. Nor can we just drift. Some effort has to be made to ensure growth takes place.
John W. Ritenbaugh
Other Forerunner Commentary entries containing 2 Peter 3:18:
1 Thessalonians 4:1
1 Thessalonians 5:21
2 Timothy 3:1-5
2 Peter 1:10-11
2 Peter 1:19-21
1 John 2:1-6