Albert Barnes Commentary 2 Peter 1:8

"For if these things are yours and abound, they make you to be not idle nor unfruitful unto the knowledge of our Lord Jesus Christ." — 2 Peter 1:8 (ASV)

For if these things are in you, and abound. If they are in you in rich abundance; if you are eminent for these things.

They make you that you shall neither be barren nor unfruitful. They will show that you are not barren or unfruitful. The word rendered barren is, in the margin, idle. The word idle more accurately expresses the sense of the original. The meaning is, that if they demonstrated these things, it would show:

1. that they were diligent in cultivating the Christian graces, and
2. that it was not a vain thing to attempt to grow in knowledge and virtue.

Their efforts would be followed by such happy results as to be an encouragement to exertion.

In nothing, in fact, is there more encouragement than in the attempt to become eminent in piety. On no other efforts does God smile more propitiously than on the attempt to secure the salvation of the soul and to do good.

A small part of the exertions which men put forth to become rich, or learned, or celebrated for oratory or heroism, would secure the salvation of the soul. In the former, also, men often fail; in the latter, never.