# these things

This refers to faith, virtue, knowledge, self-control, endurance, godliness, brotherly affection, and love, which Peter mentioned in the previous verses.

# you will not be barren or unfruitful

Peter speaks of a person who does not possess these qualities as if he were a field that will not produce a crop. This can be stated in positive terms. Alternate translation: "you will produce and be fruitful" or "you will be effective" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-doublenegatives]])

# barren or unfruitful

These words mean basically the same thing and emphasize that this person will not be productive, that is, they will not do good works as a result of knowing Jesus. Alternate translation: "unproductive" (See: [[rc://en/ta/man/translate/figs-doublet]])

# in the knowledge of our Lord Jesus Christ

You can translate "knowledge" using a verbal phrase. Alternate translation: "through your knowing God and Jesus our Lord" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])