“For if these things are yours and abound, you will be neither barren nor unfruitful in the knowledge of our Lord Jesus Christ.”
“Unfruitful” is a metaphor that comes from trees and fields. Metaphorically, “unfruitful” means works or deeds that produce no fruit (Mt 13:22; Mk 4:19; 1 Co 14:14; Eph 5:11; Ti 3:14; Jude 12). Thus, figuratively, “unfruitful” carries the idea of being useless or unproductive.
Eph 5:11, “And have no fellowship with the unfruitful works of darkness, but rather expose them.”
“Unfruitful” pertains to being useless in the sense of being unproductive. This person will have no harvest or fruit.
We need to recognize the moment of the harvest and seize its opportunity.
Some of us do not seize the season of opportunity. We sleep when the fruit is ripe, and the harvest is ready. People in need of Christ come into our presence, and we do not recognize their spiritual need for Christ. Spiritually minded people are in tune with that need. As Jude says, we are so busy “serving only” ourselves that we cannot see the need to share Christ with someone else.
Eph 5: 14-16, 14 Therefore He says: “Awake, you who sleep, Arise from the dead, And Christ will give you light.” 15 See then that you walk circumspectly, not as fools but as wise, 16 redeeming [buying up] the time [season], because the days are evil.
Jude 12, “… serving only themselves. They are clouds without water, carried about by the winds; late autumn trees without fruit, twice dead, pulled up by the roots.”